I suppose a threshold question might also be: is Thailand's reputation as a haven/Mecca for transgendered people/culture (and I suppose this is primarily male-to-female transgendereds that I'm thinking of) deserved? And are the cultural and historical trends that led to this level of acceptance uniquely Thai, or do they extend also to neighboring countries and cultures?
I think you've got a somewhat false perception there. It is quite a conservative society in many regards, pornography is banned and the internet is heavily filtered. And "Thai law currently does not recognize same-sex marriages, civil unions or domestic partnerships and it is unclear if a same-sex couple or an individual LGBT Thai would be permitted to adopt or have custody of children."
That said it is generally tolerant and it has been progressing steadily like many countries when it comes to attitudes toward homosexuals.
But there are still no anti-discrimination laws in effect.