Politically moral or morally political?

I have a terrible habit: I am political on social media. Mostly Facebook, where I am likely to encounter folks with whom I went to high school. I grew up in a suburb of Kansas City, in an area with an unfortunate confluence of new money and small-minded Kansas semi-rural folks. When I was in high school, it was a moderate Republican area. In that way that Kansas politics have gotten more and more crazy over the last fifteen years or so, it's a hard line conservative area, now.

So I still have a few acquaintances from high school who are in the area, or in Kansas generally, whose politics have mirrored the shift that's taken place in the area.

When these two facts align just so, they can result in some unpleasant conversations.

Recently, after a long conversation about the FDA's reversal on Plan B, a man I knew in high school weighed in that the decision was to be mourned because it would lead to an increase in murder, an increase in fornication (yeah, he really talks like that: he's a minister in a fundamentalist sect) and would take children away from the moral guidance of their parents.  We talked a bit about some of the underlying false assumptions in some of the above--Plan B is not commonly regarded as inducing abortion--without much progress--and then he said something that I have had stuck in my craw ever since:

I hardly ever write about strictly political issues. that is not to say that i am without opinions, but they are not my prime concern. You assume politics because it is the forum is which your discern truth.

See what he did there? He's got God and religion, and that informs his politics. I've just got politics, like some kind of modern day Lucrezia Borgia, who is political...and amoral, because of the imperfect forum I use to 'discern truth.' He doesn't say it outright here, but he has implied before that my politics are at best "humanist" and at worst...utterly divorced from moral considerations. Nevermind how clearly untrue that is: I'm not HIS kind of religious (and very few people are!) but the assumption that I am therefore immoral/solely political makes me want to hand him a box of genital punches.

I guess I don't have a conclusion about why this bothered me so much, except that it's so emblematic of the cultural script that people of fundamentalist faith impose on people who are different from them. I encounter it so rarely, but this was really subtle, and it's left me cruising for a fight that probably isn't merited by how it was presented, and talking about it would require resurrected an old thread in an off-topic way.

That's why you all get the rant here, I guess.

What would you have said in my shoes?