"How could somebody like Milo support Trump if the President was anti-LGBT?" they asked.
The answer is simple: Yiannopoulos is a provocateur. He could care less about Trump or other LGBT people. He's simply using Trump as a way to promote himself.
Mass media has no shortage of LGBT writers. With few exceptions, their politics are progressive and left of center. So to stand out in the crowd, a LGBT writer has to be distinctive (as is also the case for any non-LGBT writer).
If he was left of center, Yiannopoulos would just be another one of many. A few LGBT writers stand out because of their special talent, but that's not something you can force on yourself.
However, by acting like he was far right of center, and obnoxiously strident to boot, Yiannopoulos was alone. No other LGBT writer was way over there with him.
Ergo, by positionining himself far on the fringe, he became distinctive by saying and writing all sorts of outrageous, provocative statements. He made himself newsworthy to the conservative press: see, we're not bigots and haters, because we're listening to what Milo has to say. Look at us being inclusive!
Yiannopoulos is not the first one to do this. A small number of people from protected classes have made names for themselves by siding with the straight white male patriarchy and shitting all over other people in protected classes.
He isn't even the first LGBT person to do this. Tammy Bruce did that long ago. She was left of center until the mid-1990s, then decided changing her stripes would make her more marketable. It worked.
The bottom line to all of this is that Yiannopoulos's public posturings and outrageous statements are irrelevant when it comes to Trump's anti-LGBT policies and close friendships with anti-LGBT zealots.
No amount of posturing by a self-promoting provocateur like Yiannopoulos will change that fact.