Never Split the Difference. And Nonviolent Communication.
Because just listening to others, and showing that you care about and understand what they're saying, can go a long way. Not always a need to actually do anything in the real world (or to say or pretend that you agree).
Maybe theoretically this won't place you in their old group, still, you'll a bit form a new group where you and that other person are friends
These tactics are just that, they are not strategies. They are not long term successful or sustainable.
It seems you haven't read any of the books.
I did use the listening technique in Never Split... and it worked well, and long term good effects too for everyone. -- When listening to the other person, one gets a bit more open oneself -- sometimes the other person does have (partly) good ideas (although not in that case) and it's simpler to find something that works.
And while it is true that some groups hold language and ideas that are both infectious and dangerous, arms-length exposure to many such ideas is much less likely to result in pathology than close exposure to one. Refusing to learn an enemy tribe's language is an uninformed bet that you lucked into the best tribe by default.