(you do sound like you're throwing a tantrum tho? calm down)
uke did his best to defend himself. the pedobear is bigger and wider than him, who knows what will happen if he resisted. the creeper might get violent and rape him instead to silence him. uke did find it disgusting so he figured that if he finger himself and think of the seme, he won't get fucked by the creeper so he just did it.
also, if anyone is suddenly assaulted by a flasher/sexual harasser DO YOU THINK THEY COULD THINK FAST?
The uke in this manga is a fucking no like NO. N O. he's such a bitch? and I definitely don't like when an uke is like that with a rapest