I’m curious why you would be interested in public groups on Simplex? Its great for direct messages and small friend/invite only groups. But what would you gain in terms of privacy with public groups? If the challenge to entry is “click this public invite link”, you should assume bots are joining and scraping anything with triple digit member counts. If your threat model is focused on corporate surveillance, public group chats aren’t that much different than community forums that lack a bot friendly API for scraping. Which is to say, very easy to scrape still if anyone actually cares to.

As others have mentioned, the moderation tools are basically nonexistent and bigotry runs rampant. Even if you try to organize alternative groups to the Nazi bars, you will not have any tools to stop organized harassment.