Remember that N.K. Jemisin post I linked to a couple days ago? Livejournaler Delux-Vivens linked to one of Jemisin's later comments that I hadn't seen, and I want to make note of it, because I think it's a really excellent rebuttal to "The Tone Argument":
Yes, I think the "quiet reasoning" would've been missed without the "angry" posts. But I'm putting scare quotes around these for two reasons a) because the "quiet reasoning" posts were angry too; very likely every cogent and persuasive post you saw was written by someone trembling with fury and struggling to be coherent. And b) because I don't recall seeing a single "angry" post that didn't make a reasonable point...
<snip>
As for the danger of alienating people with good intentions -- well, one of the things that I learned from RaceFail (and also from general experience) was that people with good intentions are the ones to fear most. The overt racists are easy to deal with. You can spot them coming a mile away. But the well-intentioned people are scarier. They might not intend harm, but in most cases they haven't thought about all the racist (and other "-ist") messages they've absorbed from society. They haven't done the basic groundwork necessary to purge themselves of that passively-absorbed "-ism". So they say the most incredibly hurtful, self-absorbed, and utterly useless things, then compound the problem by getting upset when they're called on it. I liken these people to sleeper agents -- they seem OK at first, but then they suddenly "activate" and stab you in the back, and then they come out of their fugue and freak because there's blood on their hands and they don't know how it got there and they refuse to accept that they're the ones who put it there, OMG, OMG. Meanwhile, you're on the floor bleeding out, unnoticed because of their histrionics.
I oughtn't quote the whole comment here, but you should really go read the response in its entirety -- and read this similar post as well. It's yet more proof that Ms. Jemisin is a really smart and very talented writer, and gives you all the more reason to go buy her book. Not convinced yet? She has three sample chapters online at her blog.