Not an expert, but: they collect funding for "autism research" with includes, among other things, identifying the genetic signature of autism, which implies prenatal testing, which implies elective abortion (as with down's syndrome, but as of yet there is no way to discern genetically between high functioning and low functioning autism). They wish to cure autism and see pretty much any degree of autism as severe... for instance the kids I saw in that autism speaks video did not look too severe to me (at least compared to my son) but I'm sure they would consider them to be severe and in need of heavy fixing.
Again I would like to bring up the issue of what is high functioning VS low functioning in a practical but not necessarily clinical sense. If an individual can use the bathroom, feed, bathe, clothe himself, but is non-verbal, is he considered high functioning? Is a verbal person who can't support himself considered high functioning? Where do we draw the line? And more significantly, where would parents draw the line, if prenatal testing ever can discern between high and low funtioning autism?