There's a big difference between venting about a crap experience you've had, and saying "all neurotypical people are stupid/intolernat/bigoted/make me want to scweeeeeeeeeeeeeeeeeeeeeeeeem."
Venting is great. We all need to vent. But if that means making blanet statements about every single person with a particular neurological configuration, no, it's not OK. If you think it's wrong to make statements about how "all Aspies are..." then you have a responsiblity to NOT make similar statements about NT people.
Oh, yeah, I vent all the time (in fact I think so much that I'll start venting to a friend and notice that they really don't want to hear it - I think I do it too much, which is one reason the Internet is great). I vent on AFF, I vent on my blog, and to friends and family. Come to think of it, usually the people I vent about are NT. But I don't write up a blog entry saying, "I've gotten so much crap from NTs, NTs just don't listen and live in their own social little bubbles".
True that some people give me crap, some people just don't listen and some people live in social little fantasy bubbles. But that doesn't give me any right or accuracy to put all NTs into this awful box.
And about generalizations - I agree with EZ that there's a difference between that and outright bigotry, but as bigotry is primarily in generalizations, for clarity's sake I feel compelled to put examples of each.
For instance, there's a huge difference between "NTs have a hard time understanding me" and "NTs are jerks who refuse to understand me".
So anyone who wants to vent, feel free to do it, but you can well vent (even saying pretty scathing, nasty things) without spreading bigotry towards a group. Just because autistics don't have the kind of power to act on this bigotry in a dangerous way doesn't mean it's less wrong than the kind of bigotry that's towards autistics and from people with more power.
While these issues ought to be aggressively attacked by all in this community, I do agree that it is a minority on here who make these kinds of statements (however noisily), and that AFF is going into a good direction towards handling this.