I think this is what the policy amounts to though, right? They're banning political discussion on their shared work Basecamp, but not anywhere else, and are even encouraging it in other private and opt-in channels, as well as employees' personal blogs, social media, etc.
That's not actually what they've said though, is it? They're moving responsibility for DEI back into HR (they call it People Ops)[0]. I have pretty mixed feelings on HR as a company function[1] and choice of profession, but that's far from a ban on DEI initiatives.
(I don't dispute your comment that committees have been dissolved.)
[0] The original "Changes at Basecamp" blog post literally says, "The responsibility for DEI work returns to Andrea, our head of People Ops,": https://world.hey.com/jason/changes-at-basecamp-7f32afc5
Other companies are able to handle peer conversations without making such a broad and vague category as politics taboo. Like you can enforce a code of conduct and treat speech of genocide as being in violation and issue a citation for a minor offense and terminate repeated or hard offenders. You can also enforce stricter speech standards on open channels and announcements while allowing workers to have free conversation in their own opt-in echo chambers.
Nuking all political dialogs just feels like a bad HR policy.