Because he's a shill.

I'm totally an ally y'all, but my gay friend said I was a homophobic asshole, and now I need reassurance since all the "queer" people I know don't agree. He must be the one in the wrong, so can you all educate me please?

*Commence TRA infiltration

Despite all of you gay men saying there's a problem, seeing it this way just doesn't sit right with me. I'm pretty sure you're wrong.

I mean, he answered his own question in the comments:

I specially need to voice my opinion on this topic because accepting his comment would be the same as saying that a straight guy dating a trans woman can't be called 'heterosexual', which I strongly disagree with.

And I don't want him to justify his orientation or change it, but I don't think it's fair of him to ask trans men or gay men in relationship with trans guys to justify why they think they can be called 'homosexual', or better put why he says he would feel the need call out a trans man dating men and claims to be homosexual

Oh, so now straight men are the authority on what "homosexuality" is?

Lesbian sisters, you don't know what this is like at all, do you ...