I doubt sportsbet vitcim was a multi account abuser, I mean sure he was definitely multi accounting but that doesn't seem like the reason he got banned. It looks like he was banned because he was trying to double spend, no matter how many times he could say "there was no confirmation, I didn't realize" or whatever in the end if you end up betting with the money that you haven't sent to sportsbet, in the end you are suspect of double spend easily.
This doesn't mean sportsbet is scam, it means you have tried to play with money that wasn't even in sportsbets vault yet which is a bannable offense. He probably did this with many accounts as well where the multi-accounting came to play, if you end up losing you are losing nothing since you haven't sent any money but if you win you are winning so it is a great strategy until you get banned.
I could also say that they allowed 0 confirmation deposits on purpose where some genuine users tx doesn't get confirmed they can lock the withdraw by saying 'double spending'. I wish they had 1 confirm requirement before crediting like other casinos. I will say it again it wasn't a double spend attempt. I don't even know how to double spend and mycellium doesn't allow to specifically mention the fees by editing. I selected 'priority' fee when sending and still they sent the tx with 0.01$ fee. And no i am not a multi accounter. They can check their system for that