I think the reason people hate them is because not only do they have enough damage to kill you, but they can survive a lot of the damage you dish out to them. Sure, everyone dies quick now since damage is so high, but if you ever play zed against irelia, you know how much harder it is to kill irelia instead of someone like lux, sona, nami, most adcs.
I just had a game where i was playing zed, i was extremely fed having 6+ kills and killing 3 unique champions on the enemy team. But when i go gank top lane, irelia is 0/2 but is still capable of killing me if i don't respect her. I can chunk her for about 1/4th of her health with an electrocute proc if i land a w, e, and double shurikens. If she jumps on me, she can drop me from 100 percent to 30 percent in 1 combo even though she is 0/2 and I'm extremely fed with more than 40 cs ahead of her. I keep trying to poke her down but sona roamed top and started healing her making her even harder to kill because she was getting heal from sona and her built in sustain. I have to also worry about sona's stun because if she stuns me im basically dead. We did end up winning but it was not easy dealing with irelia despite me having been fed and her being behind. This I feel like is the reason people hate bruisers, fighters, juggernauts or whatever you want to call them. The fact that they can be behind but still be hard to kill in a 1v1 scenario but dish a ton of damage to you if you are squishy.
It has nothing to do with skill when it comes to the amount of damage you take. The same very combo i did that requires me to land all my skillshots on irelia would melt sona from 100 percent to 20 percent easily. I can easily do that much on their jinx or mf free. But the same amount of skill in landing skill shots onto the irelia it only does about 1/4 of her hp and then after that if she is close, she can jump on me and beat me up while im on cooldown. 1 single stun or snare and im dead. I'm fed, she is behind and still capable of doing that meanwhile a fed jinx would be helpless against zed 1v1. I really don't see the balance if a 0/2 irelia > 6/1 jinx when it comes to fighting zed. I get it, jinx isn't a duelist. Well how bout this? 0/2 irelia > 6/1 lux. Cuz i can easily chunk lux down hard compared to irelia and lux actually has to land skill shots to deal damage while respecting my damage as zed.
And before anyone comes here telling me im just crying and complaining cuz i got my ass beat by irelia, remember i won that game and only died once that game so im not complaining cuz i got beat when clearly i won that.