Just curios how many people use or have used TORmail. I have in the past to email people without them knowing who I was (mostly in pentests).
In that terms I have riseup and inventati accounts. And in that case I voted wrong few days ago in this poll.
I do not use it, however if those pentests were done legally I do not see the issue. Though if you discovered a bug and disclosed it responsibly then I agree with that method. Too many good Samaritans have gotten burned doing the right thing. That service has too many unknowns. I can see that service mostly used for throw away actions and spam/phishing attacks. More than likely it has been black-holed by many online services at this point.
I use it because we run pentest from an attacker PoV. To show the client just how an attack would take place in real life we use any method that would be used by an attacker. Including remaining completely anonymous at times. I have also used it to report bugs as you mentioned. I would rather not get credit for that, to risky now. Agreed on the unkowns. It is not excepted on most registration sites anymore. Most provider consider it spam. During pentests after we are done I tell clients to block tormail for that exact reason.