> Innocent things said at work can be used against someone

No, they can be used against the corporation. And that's totally fine and proper.

> There are very many non-nefarious, completely legal reasons one might not want a work communication to be visible down the line, just as with personal. If someone can’t see that their thinking is cloudy and I bet they experience cognitive dissonance.

No cognitive dissonance here. I just don't consider private/personal speech to be the same thing as work-related speech. I think the former should be protected from prying eyes (including the government) with as much zeal as we can muster. But the latter? No, there is no reason or need to hold that stuff sacred, and many reasons related to accountability to ensure it's recorded and available for legal challenges.