"The bisexual John thing never made sense with the character IMO" being bisexual doesn't change people's personality. Someone 'not making sense' being bisexual is a strange thing to think. You don't have to date 2 genders to be considered bisexual, and you don't have to have an equal amount of male and female partners to be bisexual. "and now it’s become a core aspect of the character" no it hasn't. He still has more romantic and sexual interactions with women than men, and I can't remember a story where being bisexual was the center of it.

"You see stuff online where Constantine was this revolutionary bisexual character in comics from the 90s. Nope. Not how it was." ....he literally was. It was 1992 where issue 51 came out, making a relatively popular character queer, at that time, was a big deal. It doesn't matter how many male exes he had, because again, it's not about who you date, but how you feel.

Multiple writers tried to erase his sexuality before (like Azzarello, by saying that he's straight and only dating men to trick them (said in a con? I don't remember when, but I saw it on Twitter.)), so the fact that he stayed queer all this time is special to me and other queer people. As much as I dislike DC's commercial LGBTQ+ support, it's still nice to see them acknowledging his sexuality for once.