I think what's missing here in the moderation is the visceral reaction that people have to such a product, (to the point where their feedback seems a bit unproductive), is as much part of the conversation here as the constructive criticism.
The people who have a complete gut reaction against this don't want to enter the conversation with criticism that can seem like a negotiation with the founders, where the founders can reply with "ok we'll work on adding more cool privacy features".
They don't want to engage with the product in the first place.
However they feel that without shouting it from the rooftops, a perceived consensus might emerge that this type of product is OK bar a little privacy refinement, and thus be forced upon them by team members who don't have the same privacy appreciations as they do.
Edit: I'd like to add that I don't attribute any malice towards the founders of this. I accept that they're trying to make the right product for them.