I actually never hated Touka. Don't think I ever hated any of the characters. Touka I believe is a very important character. She was the first one to help Kaneki when he first became a ghoul and has always been there for him even when he separated himself from her. She never stopped thinking about him.
Usually it's because they want the protag with a guy or single. Pretty much her status as Kaneki's woman is the cause. If she was just a character with no romantic connection nobody would get that heated over her.
Before I read the latest chap here, there's some spoiler on instagram, that post Touka got knife on her shoulder.
And you know what, there's so many hate comment that saying they're happy that Touka gonna die. Well people how could u say something like that??
I mean, she deserve to be happy. She already sacrifices so many thing, and she support Kaneki not just burden him, but she became Kaneki's hope and support, so u hate her so much???