I'm gonna give a personal example real quick in regards to what you have said about fighting these problems.
when they are censured for the verbal or even physical violence they cause others, it only reinforces, in their mind, why they hate. it forges the toxic communities together in the fire of passion and pain.
if they are ever to come out of it, pushing them right back in is the wrong way to do it. more, the act of pushing them away hardens yourself in exactly the same way. you too become infected by the toxic hate.
understanding this, and choosing to endure being hurt, to pull someone out of that addiction, out of that fire of hate and into loving arms where they need to be, is hard.
It's all good and well to talk about what needs to be done to help these people, but in the real world things don't happen so easily.
My dad, for example, is extremely racist. When I first really got old enough to realise this, at first I was angry. I realised soon enough what you were saying, that fighting with my dad only made him more determined to stick to these beliefs. I started to take a different approach. To debate with him instead of fight him. To talk through why he felt and thought the way he did. I had to be well informed, able to refute and explain all the things he dug up online to throw at me. Over the years, I've had a lot of long and serious talks with him. I had to acquiesce on other topics, because denying everything that he believed (no matter how gently, or intelligently) had the same effect in shutting him out. I had to create common ground to approach him on, even if that common ground was a fallacy. It was work, and It sucked, and it exposed me at a young age to a constant stream of vitriol and regressive views. I did it anyways. I loved my dad, and I fought for him. By the time I graduated highschool, I actualy saw real change in him. Maybe not a tolerance, but a more critical attitude. He wouldn't jump to race anymore as a conclusion for things, he would research things and look for other causes first. A lot of times, that research brought him to the conclusion that things weren't quite as he had assumed. I think he still had that gut instinct for racial assumption in him, but he learned not to trust it, and he was more tolerant as a result.
All of this was useless.
When I left for college, he suddenly no longer had someone to talk about these things with. No-one who held non-racist views would even discuss the issues with him, because society has conditioned people to immediately reject and shun people who exhibit any vestige of regressive beliefs. Like you said, he turned to like minded company because those are the only people that would talk about it. It dosent matter how much you try to help someone, if society rejects the problem, they will be rejected and return to the problem.
This can be overcome to some extent with a problem like alcohol. If the person can obtain some objectivity of the situation, they can recognise how they have a problem, and persist despite societal rejection. This is possible to do with an external problem like alcohol or tobacco. With internal things (like racial hatred) It is almost impossible to separate it from thier personal identity.
Anyway, I came back from college last summer and was shocked at some of the things I heard coming out of his mouth. It was worse than I ever remember him being. I think a lot of it was stirred up by the election this year too. He is a staunch life-long republican, and hearing his side constantly berated by the media as "deplorable" and racists (even if there was some truth to it) drove him back to being such. He couldn't turn on the TV without seeing people mocking and demonizing his side. He couldn't stop to examine what Trump was saying for himself, because it was a challenge. To question his own side, that was what these people wanted. That was defeat. He had to fight. It didn't matter what the republican base was saying, it was his side and he had to support it. It didn't help that a lot of what was being said was right in line with that suppressed gut instinct. He latched onto that community and it put him right back to square one.
I dont have the energy or the time to support him anymore. I love him, but I can't do it. It would just be a waste of my time, and a bad influence on me. It dosent matter anyways. No matter how much you love and support someone, no matter how much you fight for them, and wait for them, it dosent matter. Society has the final word.
I know that sounds pessimistic, but it is the truth. The only way you can help them is if they are helping themselves, and if they are helping themselves then they probably don't need you to be helping them anyways. In the end, there's nothing you can do but grit your teeth and mind your own business. What is, is, and you can't change it.
What makes me even sadder is that I can see how it has affected me. That gut instinct i kept talking about? I have it to some degree to. I'm aware of it, and it's not a part of my identity. I will never let it effect my actions or change the way I think, but it is there. I hate that. I hate that I have to have that. The thing is, it probably wouldn't be there if I hadn't put myself at the forefront of his own problem. If I had just grit my teeth and stayed silent whenever he said something like that, I probably would have turned out fine, if a little estranged from my family. I'm quickly becoming estranged from them anyways.
My point is, what you propose does not always work. It's the difference between theoretical physics and physics in the real world. Sure, in a perfect world that would be the optimal course of action, but in the real world it often just gets more people hurt.
I hate to say it, but some people are beyond help. All you can do is try to save yourself, and get out as soon as you can.