There's a good reason why people shun those who voted Trump, even if they're close family members:
Voting Trump isn't just some random mistake you made, or a choice to believe some guy who proposes things you may not like may solve problems that are more important to you.
Voting Trump implies accepting or overlooking a lot of things that are so out of line, so unacceptable and so immoral that it can't be seen as anything other than a major character fault: if you vote Trump, you're either actively complicit or you're a complete lunatic.
No matter how bad your problems are, voting Trump simply can't be an option unless you actively agree with the heinous things he proposes, and nobody with a shred of decency wants family members like that. That's why Trump splits families like no other politician in US history ever has.