You have a point, which is why there are countries in which your gambling profits are not subject to pay any tax, but there are some silly governments which say that you are supposed to pay some money out of those profits, however this is a very difficult rule to enforce, especially when we talk about physical casinos in which the majority of the bets are made in cash and you can decide to receive your payment in this way as well, making very difficult for the government to know that you earned any money unless it is a big amount.
Taxation only affect the gambler with less profit from the game or the gambler who never get a chance to win the game in the gambling.If the gambler made the enough win from the gambling sites,it’s enough for the gambler to pay the ten times of the taxes for the gambling sites.When the gambler receive the regular money.He can pay the taxes to their government by the way of the bank.So the bank can easily monitor the winning of the gamblers based on their transaction with the gambling sites.The gambling sites also help the gambler with the immediate deposit of the winning to the game.So they huge money in the wallet of the winner of the gambling to pay taxe
More taxes should be applied to gambling site owners who are business people with definite income from gambling. Moreover, I sure that if such tax is implemented, most gamblers will hide their gambling history and winnings so as not to be asked for tax.
The government should be more tolerant of every gambler because they are just someone who comes to gambling sites to spend money as a form of entertainment and pleasure, not to make certain amount of profit.
I know that some countries impose tax revenues to be allocated to disadvantaged communities, but 50% of gamblers are people from lower middle economic levels so if there is too much emphasis on taxes on gamblers it can also make things difficult for them financially.