The Internet has been wonderful for us writers, among other things, opening the floodgate so we can participate in on-line critique groups and get feedback from authors worldwide. And sometimes there are other reasons why it's a good thing they live in Antarctica, such as when they shred your novel and you want to take a swing at them with your aluminum bat...
In my years of shepherding tens of thousands of authors in the Critters Science Fiction, Fantasy, and Horror Writers' Workshop on the Internet--and similarly for a good decade before that running an Internet service provider for tens of thousands of users exchanging messages--the most common complaint I've had the "joy" of dealing with has been of the "what so&so said was devoid of content, and mean-spirited, and I want you to beat them up for me" variety. I've traced the source of these complaints, almost universally, to one root cause: Failure to communicate.
The underlying problem is rarely that the "attacker" said something vacuous or even incorrect. As judge and jury, I try to view what they say in a neutral way, allowing great latitude for freedom of speech. I almost always find that the critiquer had some valid points. Well, it's their opinion so it's valid by default; but you know what I mean. There's a kernel of truth in what they say.
The problem is How They Say It.
When I point out what's going on, the reviewers invariable defend what they said. "But it's true that..." And perhaps it is. The problem is in how they phrased it. It's the old Form vs. Function dichotomy. The content may be fine, it's the presentation that's lacking.
I know, it's easy to write something like this (which is the beginning of an actual critique):
Use a spell-checker! NOTHING detracts so much from a story as bad spelling and/or grammar! For example, you spelled 'incessant' as 'incesint'. AGH! Also, you must put in commas where two independent clauses are joined in a sentence.
Are these factually correct statements? Probably. Did the author grasp this from this critique? No. The author complained to me that the critiquer must have had a vendetta. The author didn't want to hear the message, and used an extremely convenient excuse not to--that the message wasn't really meant to be taken at face value, but was merely some kind of revenge thing. It wasn't, but that's lost when you employ this tone.
"You need to," "have to," "should," "must," "can't," "don't," "!", ALL CAPS, the imperative mood--these are harsh and demanding. Readers (especially authors having their babies appraised) react to the haughty tone, and often ignore the message.
So what should you do? If the manuscript is so awful, so riddled with typos and grammos that you feel personally insulted they had the nerve to waste your time and you want to grab the author by the throat, my advice has always been, Skip that manuscript. Pick another one if you have choices or if you don't, make polite excuses why you didn't have time to read it. If you feel you absolutely must offer a critique, then Suggest, don't demand. You don't know their circumstances; they may be a twelve-year-old quadriplegic trying very hard. Think of it as a twist on the old adage: "If you can't say something nicely, don't say anything at all."
"I'm not sure but," "you might consider," "have you thought about," "another idea could be," "possibly," "maybe,"... these are the hallmarks of a tactful, softer phrasing:
I noticed a number of what seemed to be spelling and grammar errors in your piece. For example, I thought you meant "incessant" for "incesint"; and my ear wanted to hear a comma between the independent clauses in your sentence, "I came I saw I conquered" (which I would write, "I came, I saw, I conquered" -- unless you're shooting for a run-on sort of style for literary effect, in which case, though it didn't work for me, "nevermind" :-).
The entire point of communication is to communicate. This point seems frequently forgotten.
Your job as critiquer is not to crush the fragile ego of a budding writer, but to help them become a better one.
Yes, sometimes whacking the reader over the head is an effective means of conveying your message: If you're in a position of power correcting a grievous mistake (coach reproaching a team member, or commander vs. soldier); or where offense is implicitly accepted as possible (editorial exhorting readers to vote against ballot proposal X); or a situation where offense isn't likely in the first place (a mass-market "how to" book, or yours truly writing this article to a wide, generic audience).
Critiques are none of the above. An author offering you a piece for critique is not empowering you over them as a lord and master (and acting as such is asking for trouble); nor is offense implicitly expected from a critiquer (dislikes, disagreement, sure, but not rudeness); nor is the author a generic audience to you--indeed, they're a very personal, one-on-one audience.
A request for critiques is a request for constructive criticism, not destructive, both in content and phrasing.
Remember, Write for your audience. In a critique this means, without any exception I can think of, that you need to phrase your critiques delicately, tactfully, carefully. This isn't the same as only saying nice things; no one is asking you to lie or withhold your opinions. It's "merely" being polite when you say you didn't care for something. Is this hard? Damn right. Wouldn't it be great if you could just say what you meant? Sure. But who ever said critiquing was easy?
"But readers and critics are harsh," you say. "An author has to develop a thick skin." Yes, but readers and critics (as opposed to critiquers) have a right to be harsh. Readers pay money for the author's work, and may rightfully feel cheated if it didn't fulfill its promise. A critic's job is to tell readers whether something's worth their money or not. Neither reader nor critic owe anything to the author. A critiquer's duty, on the other hand, is not to thicken the author's skin. Your duty is to help the author improve their piece.
Of course, you can take the cop-out approach, and say, hey, I'm a blunt, gruff sort of person, I tell it like it is, that's just who I am, live with it. Well... if you do it that way--to be blunt--you're wasting your time. Don't bother with the critique, since the author won't hear you. They're too busy with their rising blood pressure and thoughts of playing Mark McGwire with your head.
You won't have communicated. So what was the point?
Yeah, you might feel better for having vented. But, criminy, go punch a hole in your drywall or something instead. Don't take out your frustrations on an author.
"No, honest," you say, "I didn't mean to! I really was trying to communicate what I thought were the flaws, and oh boy, did it have flaws..." Ok! Great! Just consider that the method that works is to be tactful about it, not blunt. Put another way, skip the "brutal" part of "brutal honesty" in a critique since simple honesty does the trick.
Remember, the pied piper led the rats and children away with a sweet tune, not barked insults.
It's not what you say. It's how you say it.
There are also some examples of problem resolution cases I've dealt with and specific wording suggestions.
For those with a mathematical bent, here's a mathematical look at the matter.
And when you're done with that, you can run your critique through Aburt's experimental Diplomacy checker to see if it finds any red flags.)