…yeah there shouldn’t really be a debate about whether one has a right to ask someone to be respectful but with this person, it’s impossible to have that conversation without getting accused of being the problematic one. And as a survivor of abuse, that’s very triggering for me because abusers are very adept at turning the tables on the people they wrong/hurt to make it look like it’s those people who are being problematic if they speak up at all

That’s probably my biggest issue at the moment, how triggering the whole situation is for me…
I think you have him pegged…and actually, he sounds worse than I first thought he might be. He’s not just willfully misinformed about what “weakness” is. He’s someone to be wary of yourself.
Like most abusers, he uses the tactic in which it is everyone else’s job to convince him what the boundaries of others ought to be. He is the “customer” who is entitled to be “right” and to whom “the sale” must be made, while the whole rest of the world is the “sales staff” whose job it is to satisfy him. It never occurs to him that the whole rest of the world might simply say, “Who do you think you
are, anyway?” For him, it is so obvious that the world revolves around him that to imply otherwise is tantamount to picking a fight with him.
Once you identify someone who does not have concern for others as any kind of guiding force in his life, the way to deal with him is to deal with him as little as possible. Do not trust him, do not interact with him, do not engage with him in debates, do not believe anything he has to say about you or anyone else, whether it is abuse or flattery, do not pity him, and most of all, once he has let you know that he cares nothing for your concept of “redemption”, do not try to redeem him. Not only is it not your job, redeeming him by use of reasoned argument is an impossible task. Shake his dust from your feet. As a formerly abused person, this is going to be an on-going project for you: That is, to identify those who abuse, and to remind yourself that no one who abuses deserves or will benefit from receiving your respect or a moment of your efforts to appease them or to educate them. If they can’t use you, if you are not content to revolve around them in their self-centered universe, they don’t want you. You are deserving of love, and when you are around someone who simply rejects the entire notion of love, you are deserving of better company. Do not feel bad…they will not profit from the benefit of your company, either.
Some abusers simply lack appreciation of the boundaries of others. The way to impress them is to simply draw the boundary and insist upon it. You don’t “sell” them on your boundary; you defend the boundary and do not allow anyone else to question it. Others lack self-control. Well, in that case, you stay out of any geography in which they are free to act. If you have to meet them at all, you only meet them on ground where others have the authority, capacity, and the will to control the uncontrolled when they lose it. Others, the sociopaths and the psychopaths, not only reject the idea that any boundaries whatsoever are appropriate for them, but see it as a throwing down of the gauntlet when anyone else tries to draw a boundary. Just stay off the radar of such a person. Stay out of their orbit as much as you can. They can be vindictive and covertly aggressive. Yes, they can be evil to the point that they’ll take a hit themselves if it means getting back at someone they want to “get”. Really, don’t take them on, it never helps anyone.
Some people come out of these categories when they quit their addiction or when they face up to their self-centeredness. A person like that will approach you with a purpose of amendment, and without making excuses for their prior behavior. In that case, you can consider whether you want to try a new relationship.
Keep in mind the story of the Prodigal Son. The father in the story didn’t go after the Prodigal like a lost sheep. Why? Because the Prodigal was not merely errant, but willfully errant. This is why the Prodigal’s father waited for his son to come home. The son had to present himself for a new relationship before a new one could be forged.
IOW: Failing to engage with him is not tacit approval. Rather, when he starts up with this stuff, just walk away or just let his rude comment lay there without any comment from you at all. Don’t engage him. Let it go. Don’t cross him. If anyone else things you ought to have a round at quarrelling with a concrete wall…you let them have at it. Be smarter than that yourself, because you’ve been there and done that.
Avoid this person, and use your efforts to tend to the people he hurts, if they are aware of his badmouthing. Otherwise, ignore him. He knows what you think, and you know how interested he is in correction. Anything further is throwing pearls before swine. Don’t do it.
BTW, you are never going to turn into him. It isn’t going to happen. If he says you are, it is another one of his self-serving lies. Repeat that to yourself as often as necessary. The devil is a liar, and lies are the foundation of the abusive life style…lies and cruelty. Avoid the person who deals in either one.