You’ve both come to the right place… and also the wrong place.
Right because you’ve correctly assumed that I deal with this a lot. Wrong in that… I have any helpful advice.
To be completely honest with you, I am fascinated when people hate characters I love, and my irritation and grief with it only truly comes into play when digging into their rationale reveals they’re either misinformed or have chosen very superficial/inconsistent reasons to fuel their hate. It’s not just Jason subjected to this, but I honestly find most of my favorites are always possessing some amount of unreasonable insults and hatred in the fandom for reasons I just could not get.
Like there was a guy for a while who would reblog any post I had where I discussed Cass on a hypothetical team-up or headcanon with other characters with “UGH I hate her” tags or “EVERYTHING’S PERFECT EXCEPT FOR ONE” and when I started calling him out and asking why, I’d get nothing.
Like cool you don’t like her, but explain to me why you feel so strongly you have to reblog a fan with such ire!! Surely you have a REASON behind all that disdain to cause you to go through that much trouble!
… um. I don’t exactly advise my method, though. Obviously it’s not worked out wonderfully for me in the past.
My best advice, actually, is to surround yourself with fellow fans who enjoy your favorites right along with you, and if you have the time and stamina, try finding a fan who dislikes your favorite but is respectful and intelligent about it and read up on their opinion on the matter. Sometimes great points can be made that you never thought of before and can help you either appreciate some of the rougher edges to your character you can acknowledge and deal with as a fan or give you something to base research and argument over for your own satisfaction. But doing step one (finding good posts you agree with) to help your resolve is definitely something you should do first.
Just remember that everyone’s entitled to an opinion. And sometimes those other opinions can be surprisingly revealing and well founded! And then spend hours drowning in canon to feed your argument as to why your favs have value outside of those brought up circumstances anyway. You might learn something and you might end up loving your favorite more and maybe for different reasons.