> That's literally the only thing I'm scared about going to US
Don't be. TSA is stupid theater, they suck, but probability of anything happening to you is very low. Probability of anything beyond mild irritation happening to you - unless you one of high profile people that Powers That Be have a beef with - is vanishingly low.
Yes, it still happens - millions pass through TSA every day, and you'd have a number of cases where usual silliness rises to the level of dangerous idiocy, and these cases would be widely publicized and criticized, as they should be. But pure numbers game suggests your chances of becoming one of those is very small. If you take some basic precautions - like not standing out too much, being polite and not arguing with them, however stupid the proceedings look, etc. - even smaller.
In fact, on my latest travels, I personally have had much more irritating experience with London security that with TSA. On top of everything TSA does (which they did too), London people were severely understaffed for some reason, but if you think that made them move at anything faster than a glacial pace, you'd be so wrong. They were so Zen I'd be envious if I wasn't so concerned about missing my flight because they need to swab my books and slooowly bring it to some mysterious machine and slooowly come back and so on... But still it wasn't much more than mild annoyance summarily.
> But I am scared I'll get into trouble on the border because of my HN and Facebook posts (e.g. against US drone strikes).
Nobody cares. Really. They don't have resources to read every HN thread.