It seems that all the vices are immoral only until the government can profit. drinking, drugs, gambling and prostitution were all once froned upon. Then it became essential to tax booze to help pay for the New Deal and prohibition was repealed. Cigarettes should have the age of purchase raised from 18 to 21 but that would decrease revenues.
Online gambling will be legal as soon as politicians can find a way for it to benefit them. Per haps they will do the same to prostitution. They will argue that online hookers wil not be abused by pimps. That would make it, and the tax, an act of compassion.