I'm struggling to imagine what kind of political thing you would say about school. I can't share my thoughts on the school board, pedagogy, common core, racist school names, etc? Doesn't seem like an onerous restriction and I can't recall ever having a work conversation that would've violated it.
These can all be interpreted as political issues, and I think very reasonable to talk about. The policy is so arbitrary that it ends up being that you can't talk about things that the founders don't want you to talk about.
I get the sentiment, but the execution is chilling.
In the absence of clear policy, it comes back to trust, which needs to be earned and can be lost. I don't work at Basecamp, so I don't know whether they "deserved" to lose trust and my opinion doesn't really matter. But the evidence appears to show that trust was dead, whoever killed it.
We all saw what happened, and we're talking about it because most of us think things could have gone a little better.