Speaking as someone who grew up on the comic books, saturday morning cartoons and movies, all aimed at things like comic book heroes to ninja turtles to thundercats to superman and batman and x-men and all that, when I was young I use to be drawn to these characters, because at the end of the day the fundamental basis of their character were that they were heroes, doing the right thing, never stepping out of line from there moral code and beating up anyone who threatened that code.
You have guys like superman beating up bank robbers or multinational heads of organizations because they do questionable things, or batman who will NEVER kill someone because of how his parents died, so he will never kill any of his supervillains, even ones that will never be redeemed like the joker. These whole ethos of how heroic characters do the right thing, don't kill, don't steal, don't go above the law, and always stop those who do is what I grew up on since I was a kid.
however, in the last decade my whole outlook on heroic deeds in comics and movies and tv has shifted a fair bit since those times, and while there will always be a part of me that will love these heroic characters, I find it hard to take them as serious mediums now as what I did years ago. What I read now, see on tv and in films, are fictional characters who have a darker edge to them, and not just for looking, I notice this theme seems to have become stronger in the last decade to what it was in the 80s-90s.
One of my favorite comic book series in the last decade has been the authority, where the 'heroes' in these comics don't split hairs, they don't hold to a spotless moral code of coduct like superman or batman, they outright kill their enemies in the most brutal way possible, and when the next enemy comes along, they kill them to. Infact in the comics the characters get involved in international affairs and kill dictators in other countries and slaughter their followers because they can.
You take it from tv shows too, shows like Dexter where he's a serial killer, but your rooting for him to kill because of how he does it, or games like god of war with kratos butchering anything in his path or lords of shadows where instead of fighting against dracula as simon belmont, you ARE dracula, drinking blood and making bodies explode.
I'm comparing how heroes in fictional media has changed from 20-25 years ago, to what people enjoy to see more nowadays. Is there a more darker tone in what we perceive as likable traits in 'heroes' now? I personally think something changed in that time where its become more acceptable to have darker heroes as the standard in fictional mediums then your white washed heroes like captain american or superman. Infact I think they even try to make these white washed heroes darker because of the times we live in, looking at the last superman movie and what he did at the end of it.
I think also thats why films like guardians of the galaxy worked so well, because of the changed opinion of the time and why it might have been a little more controversial 20 years ago, swearing, drinking, killing, things you'd not expect from comic book heroes mainstream back then, where as now its more acceptable.