I think when trying to refute or explain gay or trans pride and suggesting a corollary in being proud of being autistic, that it is vitally important to refer to the meaning of "pride" as used within the LGBT movement.
http://en.wikipedia.org/wiki/Gay_pride
Quote:
Gay pride or LGBT pride is the positive stance against discrimination and violence toward lesbian, gay, bisexual, and transgender (LGBT) people to promote their self-affirmation, equality rights, increase their visibility as a social group, build community, and celebrate sexual diversity and gender variance. Pride, as opposed to shame and social stigma, is the predominant outlook that bolsters most LGBT rights movements throughout the world. What’s more, pride has lent its name to LGBT-themed organizations, institutes, foundations, book titles, periodicals and even a cable TV station and the Pride Library.
It is about taking a stance against discrimination and violence and building community. It is meant to oppose shame. It is not about achievements, which is not the only definition of pride:
http://dictionary.reference.com/browse/prideQuote:
pride
noun
1.
a high or inordinate opinion of one's own dignity, importance, merit, or superiority, whether as cherished in the mind or as displayed in bearing, conduct, etc.
2.
the state or feeling of being proud.
3.
a becoming or dignified sense of what is due to oneself or one's position or character; self-respect; self-esteem.
4.
pleasure or satisfaction taken in something done by or belonging to oneself or believed to reflect credit upon oneself: civic pride.
5.
something that causes a person or persons to be proud: His art collection was the pride of the family.
While no dictionary is the strictly definitive description of word usage, it does serve as a starting point.