I don't think Lauda wearing a Betcoin.ag signature is a big deal.

There are accusations about every single site out there. This (resolved) accusation of not awarding the jackpot if I understand correctly is actually against Betsoft. As they stated, he wouldn't have received the jackpot makes no matter which site he was playing at.
The only thing I see shady is the way they changed their terms without changing the last updated date.