Point #1 is easily enough addressed by telling people that steampunk isn't assigned reading; nobody is forcing you to pick up a copy of Pride and Prejudice and Zombies from the school bookstore and write a report on it. Point #2 has been addressed already here.
But it's worth expanding on the second point, because for one thing, what's clear from contrasting Mieville's sneering, yet grudgingly respectful essay on Tolkien's Middle Earth to the comments in this Charles Stross post is that PEOPLE AREN'T FUCKING PAYING ATTENTION. I stand by my comments in the previous post: there is not more than a tiny niche market for the unpleasantly accurate kind of steampunk that focuses on the nasty, poor, communal and short lives of the proletariat in the Victorian Era. I will also echo some of Stross' more intelligent/aware commenters, who point out that the nasty, dirty sort of thing these people claim to want is already present in a lot of steampunk/gaslamp fantasy as background, just as Cornwell's Sharpe novels pull no punches in describing the hellish world of the urban poor in Regency London. The fact that Stross and the Foglios don't focus on the poor and the downtrodden is proof that they know their market better than all these people who are whining about the "inaccuracy" of the steampunk genre. One could, conceivably, write a picaresque adventure tale in a steampunk setting, and I'm sure if it hasn't been done successfully yet, someone will soon.
But there is a reason the New Wave in science fiction died out after a few years of being the It Thing. Most people don't enjoy wallowing in other peoples' misery when reading SF and fantasy; that's what mainstream fiction is for, or horror, if you like something still within the walls of our crumbling ghetto. And that's the reason people aren't writing the kind of gritty steampunk novels these hosers claim they want.