Actually the site has no even problem on that because in the end it is the Players will take care of everything.
So this is a Win Win solution on their side , They have followed what governments given on them yet they also covered the taxations .
It's always the middle class people who get affected the most when the governments impose any kind of taxation.
That's what is happening here as well. The gambling operators don't pay taxes out of their pockets but instead they pay it from the profits they make out of their businesses.
If their business is generating less profits due to high taxation they probably increase their charges/costs/commission to make it even.
Eventually it's the gamblers who have to suffer in the end.
That's right, it's always the end-user or consumer that will suffer in high taxes in real life, in gambling, I don't know if increasing the charges and other fees would help especially if there's a healthy competition in the area, maybe gambling operators just have to focus on increasing their number of gamblers by being aggressive with the promotion or advertisement so they'll be able to increase their revenue as well.