I have a similar policy for my work at university. Not so much as a political statement but for mere convenience I have avoided going to US conferences during my scientific career so far, even though some of them were quite interesting. Too many border controls/visa requirements. It's not worth the hassle.

Luckily, it's not hard for us to get US researchers to our place for a visit, they tend to like sunny, peaceful places in Europe where you can stroll through the city by foot.