When it comes to the rupaul dragrace issue of using the word 'tranny' I think it best to first talk about the nature of language and why some words become taboo to use.
Language isn’t just a way of directly communicating, it also carries with it a rich and subtle second set of meaning from the culture that births it. Indeed there have been historical attempts to aid the suppression of a culture by banning people from using local languages and dialects.
This means some words become taboo to use because of the negative social context and histories attached to them. When someone uses such words it signals a lack of understanding or even support for the social histories and institutions that caused such suppression and violence. This is why it pisses me off whenever I hear my 'I'm-not-racist-but' uncle use the term 'paki shop' for the local corner shop.
Normally use of words with bigoted connotations are pretty straightforward. You have the Cis, white, male heteronomative majority using terms that carry horrible connotations which tastily approve the social oppression/side-lining of a cultural 'other', gay, black, woman, trans ect. A simple case of aggressor and subject.
This is where the Dragrace use of 'tyranny' becomes a little more complex.
Drag is its own culture and community, with its own histories, cultural norms and yes, from that it has grown its own language and terms. A small subgroup with an already shunned group, they have historically been the most visible section of the gay community, forgoing the luxury of passing, which has sadly meant they have often been attacked not just from the outside heteronormative culture for breaking the rules of sexuality and gender, but from homonormaitve members of the LGBT community.
Tranny has often been used as a slur against members of the drag community in its history and the culture responded by reclaiming it for their own venacular. Turning it into a general term of identification and stripping it of its negative context. Much like the larger LGBT community has successfully done with the term queer. Drag queens use of the word tranny has become a part of their cultural language.
Transpeople have also been subject to the same slur and their response has been quite different; to reject the use of the word in any context as a rejection of all the negative stereotypes and destructive, ignorant attitudes that it carries.
This is the crux of the matter. You have two societal 'others', both with a cultural/historical claim to a highly charged word. Its at this point my views become a bit conflicted. Does one group have the right to come and pressure the other into changing its internal cultural mediums? I dont think so, my gut feeling is that it isnt right to do that, and this is understandably where a lot of the anger and backlash from the drag community comes from.
drag race is a different kettle of fish. Its not the whole drag community, its a small section that has become a teaching point and gateway to a large cisgendered/heterosexual audience. This power and position means it has a responsibility. Its contribution to cultural language and dialogue will have a lasting affect on wider societies view of transpeople.
Do I think the show's use of those words transphobic? No.
Do I think it could have legitimised transphobia in society? Yes.
I guess my point is this, the drag community should be able to continue to use to words of its own culture and context however they see fit WITHIN their own community. No one else, gay straight, trans, has a right to interfere with that. OUTSIDE the drag community, like popular tv shows, then it becomes a matter of acknowledging how Such words carry cultural context for other groups, like transpeople and the damage it can do.