There is nothing I hate hearing more than dichotomous theories about people -- that is, any attempt to divide people into two groups and neatly pidgeonhole people into one group or the other. That said, I can't deny that any community has a homogenizing effect on the people in it.
This is also true of the various groups and camps of the parents of autistic children... except that they're also part of a larger community. Between member interchange, between-group exchanges, and the emphasis on support, a number of truly absurd and harmful ideas have become nearly mainstream.
It doesn't help that the quacks take as much advantage of this as they can, making as many quick bucks as they are able... at the expense of the children who they're being paid to help.
Often, however, the attitudes that these "biomedical" scams promote are more harmful than the treatments themselves... which is quite impressive given just how harmful some of them are.
Recent posts at Age of Autism have stirred up something of a storm on this topic. Admittedly, it's a bit of a tempest in a teacup -- which is to say that it's pretty darn small as storms go -- but it already produced a nice little kick in the pants for the AoA idiots.
Said article is one of the most eloquent expressions of what's wrong in the community of parents of autistic children that I've ever seen. Way to go, Michele!
Edit 7/21/2009: See here for another excellent response.