As a relatively affluent, successful adult who lives far from any family, I am freely able to disown with no negative consequences (aside from emotional ones).
Weirdly, the more aggressive/provocative a stance I take, the more on-topic discussion it does seem to get, even if it comes hand-in-hand with an onslaught of condescending rhetoric about how bad of a person I’ve supposedly become, huge disappointment, etc. So at some level, provoking an emotional response does seem to be effective at getting people to the table.
However, I worry that the extreme right crazies are the only ones coming to the table, and that in addition to failing to change their minds, I’m also burning good will and losing face with the majority of the family circle, who claim at various levels to want “objectivity” or “reasoned discussion”, or to “avoid discussions of politics” entirely. Those are the people I feel actually might be capable of being convinced.