Let's start with this --- the proprietors of this room are very good at the pool room business if their room is so busy that they need to impose a limit on table time. They obviously are offering a product for which the demand is high. I wish every pool room had the same problem.
Yes, this policy will, on occasion, cost them a little revenue, but it's fair as long as it's made clear to anybody getting onto a table that they must vacate after two hours. Surely, the regular patrons know of this policy but show up anyway.
I find this policy to be reasonable, even if it's not perfect.