"Tranny" "Trap" etc are all idk I hate them, they don't need to be said in an insulting fashion for me to cringe at the sound (or sight) of them because no matter how you say it they are degrading and insulting terms.
And going on what Maggie said the whole "used to be.." "became.." "wants to be.." thing really bugs me because really. If you identify as female you have always been female and if you identify as male you have always been male that's all there is to it in my opinion..
Unless of course you're genderqueer in which case I suppose it's different? Whatever you identify as you've always been I guess..