With any product created, you'll have the potential of having trolls. I'm sure even 7 cups has it too. And generally trolls don't attack vulnerable people to the point where they're using proxy or VPN's. Let alone on voice calls.

There's not much data of how unhappy 7 cups members are (maybe they're happy).

But neither of those reasons are good enough to NOT try something. Because you won't know if you're gonna have trolls or if your users will have a better experience from a competitor unless you try it.