I don�t understand being so hung up on the men he mentions in his past when he only mentions two out of one thousand people. Not exactly a great sample size. He also wasn�t in love with them. He had compassion for them, but that�s not the same thing as love. Tbh no matter what his sexuality is I would assume that most of his victims would be men anyway. It�s a lot easier to convince a man to go home with a total stranger than it is to convince a woman to do the same.
Well, because there is a clear pattern to it, it's all men that he mentions and not a single female. He clearly singled them out for a reason, these two are the ones that he remembers out of 1000 (handsome and shy, and never been kissed and a darling boy). And who's to say that it was compassion and nothing more? That's what it seems to you, but not to me.
As for bringing men home being easier then women, well, let me give you an example from the game, as to apparently just how easy it is to lure a female as well. In the sewers you'll meet a girl who is waiting there for Petras to take her to a party. Well, that didn't seem hard for him to convince an unfamiliar female to go to the sewer and then to the party without asking many questions. So, clearly in a world of BG3 it is just that SIMPLE.
Yes, he flirts with everyone that is true, but is not a concrete indication for his preferences, its more that he does it instinctively.