...
who is behind Bitfinex and there is no entity data, no telephone, no address, there is not even a contact form, nothing. yeah, we know, it's a criminal gang but this gang won't give you the funds back once they will exit.

Actually, at least a few people that are in the upper Bitfinex and Tether management
team are publicly known. I recently complained that the names of the executives were
removed from the Tether website, but it seems they are back there.
https://tether.to/about-us/On the other hand, @Bitfinexed posted this interesting snapshot of the Tether
website from 2015:

They obviously don´t mention that selling point anymore, but this could
theoretically imply that a lot of funds from dubious sources (e.g. ransomware proceeds)
could have ended up in the Tether reserves.
And before you say it @TheQuin, I know that this is conjecture on my part and
could very well turn out to be wrong. But I think it should be allowed to voice different
opinions in a public discussion forum.