>>45822612People don't want canon LGBTQ characters. They say they do but when it happens they ignore them and instead ship characters who canonically don't have relationships. Dawn and Cynthia get shipped a lot, Love Live girls get shipped a lot, K-On! girls get shipped a lot, meanwhile actual yuri anime barely get any viewers, let alone fanarts or fanfics. The latest Fire Emblem has four (4) different girls you can marry as a female player, yet Hilda and Marianne (canonically straight girls who just happen to be friends) have way more lesbian fanarts than any of the canon lesbians except maybe Edelgard. The same shit happens to yaoi, fans would much rather ship the main characters of shonen manga and JRPGs - even when those characters have a canon female love interest - than read an actual yaoi manga.
I'm not sure why this phenomenon exist exactly - maybe it's because shipping and fandom material lets you control the way the relationship goes rather than the canon material dictating it - but that's usually how it goes. A lot of modern creators for manga, anime and video games do this and thus write a certain way on purpose, where characters have close friendship with multiple characters of different genders so fans can ship them however they want. Shakespeare said you should write in a way that stimulates the audience's imagination so they can fill in the blank themselves - I don't think he had shipping in mind when he said that but shit, it works.
Plus, a gay character in Pokemon would stick out like a sore thumb because there's barely any straight character to begin with. Most of the characters aren't in any kind of relationship, there's nothing indicating the characters are of any sexual orientation. We assume they're straight because that's "default", but there's nothing in the game the characters are of any orientation except for the very few who are in relationships and generic trainers making off-hand comments.