You hit the heart of the problem. People are no longer acting like adults. Instead they are acting childish, petty, and small-minded. Family and loved ones should be able to enjoy each others company without politics ever coming up.
I'm a grandfather, a liberal Democrat as are my adult children (2) living in Austin. My only brother and his extended family all live near Tyler in east Texas and are all Republicans with abortion and Democrats want free stuff as their mantra to never vote for a Democrat. Just before we were about to eat our Thanksgiving meal in 2007 my brother told me he could never support Obama because he wants to redistribute the wealth in America. His wife announced we are about to sit down for Thanksgiving, no more talking about politics.
My brother and his family and mine have gotten together for almost every Thanksgiving and Christmas since 2007 and not once have we mentioned our political beliefs. I know I'm not changing their beliefs and they damn sure know they aren't changing mine so why discuss politics?