Simply not true. I am a man, I am not gay and I do so.
The spouse of a co-worker has transitioned from male gender to female. They now go by a new name. I do not see them often but when I do or when I am speaking to my co-worker about her spouse I use the name they have asked me to use as well as the correct pronoun.
I do not do this because I am gay, I do this because I am not a dick. It is no business of mine what they choose to do, but just as if someone asked me to call them Andrew instead of Drew, I call people what they like to be called as there is no good reason not to.
Another co-worker had his wife decide to change her name from Erin to Darcy. Should I have been a dick and said "no, that is not your real name, I will not call you that"?