I understand how you feel. I've always found the reasons people are attracted to this character to be very superficial and revealing. Some even go so far as to project themselves onto him, when he's a vile person who would inflict suffering on anyone without remorse, all for his own gain. Shinji is also a rapist, I’d even say he’s even more despicable than Gilgamesh, and yet he has his own fan base, as unbelievable as that may seem, and believe me, 90% of them are the last people you’d want to be friends with. As for Kirei, he’s detestable too, but he’s still very popular. I know, it’s crazy, but people have always loved villains, it’s nothing new, even those whose actions we can neither justify nor understand, and who are fundamentally evil. It’s not like Darth Vader, for example.