Liberal == cult.
Do NOT point out the emperor is naked.
Marrying someone liberal is a biiiiiig mistake. I’ve seen it in some of my friends. There is no go along to get along with these people. Any dissent is squashed rapidly. Based on my experience I’d bet your son voted for the won. Or just told his wife/her family he did for the sake of peace and quiet.
He will either convert to liberalism entirely or she will convert to conservative. Else they’ll eventually divorce. That’s been my experience. Based on his being ashamed of your views my guess is he’s either converted or currently in the process of converting.
But, I do think it's time to put the kibosh on Facebook. Way I see it, if my youngest two are that ashamed of me and my views then it's time to make a statement; you accept me, and my viewpoints, or you get none of me on Facebook.
And besides, I got better things to do with my time. Finishing creating that website I'm working on is a good place to start.
Thanks gang.