Co-operating with police isn't a 'PR disaster' when directed by a court. Checks and balances establish the legal framework for which Zoom aids the police - a court order. It's not hard.

Silently putting in a back door subverts the trust of users and is worse than having no encryption at all. If they aren't upfront with having backdoors in their encryption, how can we trust that they haven't been using encryption to just establish a false sense of security and sell the keys the whole time? It's a huge pile of bad faith.