This is an interesting move and I really don't think we are getting the whole story on what caused such a drastic change. It's interesting because, for the most part, I think it is safe to assume that most basecamp employees are liberal leaning, including the founders. My first thought was, why not just deal with these specific problem employees individually? Well, surely they must have tried. I can't imagine going public with such a drastic change if they didn't first at least try to correct the behavior of misbehaving employees. What's misbehaving? I would classify that as slinging personal insults/threats across the room. Would you fire these employees if they didn't stop this behavior? I'm not sure. It doesn't seem like something basecamp would do. In fact, it might make it _worse_ for them from a PR perspective if they did this, even if the employees were completely out of line for what is appropriate workplace conversation.
So not sure. In this situation, I would give them the benefit of the doubt(other than on the poor communication). I've never worked at a place where politics was discussed heavily in either work chat or in person (outside of friends talking with friends, which IMO, is perfectly acceptable), but I've seen some conversations (such as the leaked Github chat) that are just plain toxic and I wouldn't feel comfortable rebuttaling extreme views without fear of retribution. I personally don't think that people should have to deal with that in a work environment, but just my 2c. I guess it's just where do you draw the line, and internally, they must have hit that point.