I would only believe him if he can show the withdrawal history screenshot here.

Even if he managed to show you the screenshot, it would not prove anything. Allowing one withdrawal out of many will not make a site trusted.
Also, the only reason why i believe he is speaking the truth is that he is not wearing the 1xbit signature. If any 1xbit signature participants had posted it, I would have never believed it.
Screenshots can be faked as well so they don't prove anything indeed like you said.
Having a decentralized sort of forum has benefits but one of the biggest problems of such a forum is that scam casinos & sportsbooks can continue to operate and promote themselves despite everyone knowing they are scams. I was trying to avoid posting here because it only bumps this thread but man I am disgusted how a scam can run for so long without any troubles at all.
They have more than a hundred complaints against them yet managed to have a 4.3 rating on trustpilot somehow and continue operating. I have never used them to obviously I don't know how they work but all those hundred reports can't be wrong surely.