I think you're mistaking the relevance of his intentions as an excuse for him to continue being toxic. That's not the case at all. I think its very relevant why a person does the things they do. He still has to change and become less toxic no matter what.

If a person bullies because they have some kind of social ineptitude that makes them not realize they were bullying. That person is still a bully. However, its important to recognize if this was the case because the alternative is that he knew better and did it anyways because he knew he could get away with it.