I think for gambling sites who are operating legally yes they pay taxes in response with their base country regulation just same with gambling casino who are using fiat money casinos with permit to operate pay taxes and those small time gambling are not but consider illegal and would pay fines if ever they are caught into operation.
very risky if the current online casino does not pay taxes. this must be paid because they also need security because they do not want to netted the operation. because if it happens they need to issue a bigger fine. although I believe many online casinos are illegal
Well with the amount that they're generating everyday, its just right they pay tax dues. These gambling sites are likely being monitored by their governments so they really have to pay taxes