If you look at threads like in their Discord then problems with this get 65+ votes to change this thing with Shadowheart and Halsin, while the once campaigning to preserve it don't even reach 15.

So the vocal majority/campaigning majority against this is larger.

You also need to remember that this is not just this, bit Halsin's character. And his character has MASSIVE issues. He is the least used companion, there are multiple reasons why people dislike him, there are thread everywhere about him.

Articles are published about how horrible his romance is and how people are saying he should never have been made a companion.

The Shadowheart may seem small to some, but since Halsin's character as a whole is a disaster to many who requested him in the first place, and I have been in contact with 17 SA victims who have been severely triggered by Halsin.

Halsin fans and Shadowheart fans are currently supporting each other.

I can't promise anything will happen, but there is more attention put on this than you suggest.