I despise the section of the site with all my soul and have it on ignore for a damn good reason (I hate politics and anything related to them) but this relates very closely to me and is the reason I am that way to begin with. Hope it isn't bad if I go into my own mini story of sorts.
So one of the main reasons I ban and avoid political shit like the plague is because of the things that you mentioned with your father being something I deal with a daily basis in my house. Fox News, Rush Limbaugh, it's just those two (thank god, it's not the YT far right but it's still just as awful) but my grandmother who saved me from a really rough childhood has completely gotten into those two toxic sources and has tried relentlessly for two years to get me to "see the light" despite saying over 1000X I just wanna play video games or work on something that won't give me anxiety, yet she plays in the car radio when taking me places solely because she's convinced my occasional comments on how I don't want people at the border to die or how the president is a meme that I do not take seriously at all is a sign that I'm part of a bad generation/liberal despite literally marking on my ID that I am unaffiliated. My grandpa voted for the president but isn't a fan of his endless tweeting, and manages to have good standards by hating any sort of vulgar insults that he or Fox News throws out and really just is in a netural mindset, while my grandma has slooowly been drifting towards thinking the country is in the best state in history and that Trump has never made a single mistake in his entire term, which scares me a ton since we still have tons of fun moments together but every day she spends periods of it watching Fox news and ranting about whatever they rant about. It makes me feel like my family is not the same.
Don't even get me started on the hategroups I've seen on the internet like GamerGate making me want even less to do with political crud. There's a reason I like the VG board of this site compared to most other places is because on those sites some people will complain about a girl's skirt being extended by one inch during localization, and treat it as if it's a world-ending situation that somehow warrants them harassing and bugging the developer over it. That's the sad and dangerous part of our culture today is that people think everyone is under attack and that's why hategroups and awful people like Rush, Ben Shaprio, TheQuartering and Milo are taking advantage of younger and older people.
Heck, I still remember being an 8 year old kid, just freshly adopted and finding out episodes of Pokemon were skipped over in the US, and losing my mind due to my favorite show having missing episodes I didn't get to see to the point I became the stereotypical weeb and hated American companies for no reason because I was under the mindset they "Ruined" the show by skipping a measly four episodes. Needless to say, this stupid behavior on my part was quickly punished by my grandparents and teachers, and I got back on track and realized how stupid it was for me to feel that way. So I do agree with those saying parents not taking action is a big cause for this, and your dad should really take care of your siblings to make them not act out this way, especially with the more aggressive ones that are actually dangerous and give off creepy vibes from the sounds of your post. People can change though, although if they've been in it for far too long it's less and less likely. They don't have to be political at all, but they can still avoid getting obsessed with the bigots ruining our society