But the money can also go from the wealthy to the poor. If the tax from casinos gets collected by the government and is used effectively, it can help a lot of those in need. The money can be used to improve infrastructure, education, healthcare and etc.
Money circulate and this is beyond a reasonable doubt, people can get to gamble and earn from it, the same way the gambling operators are using money for the maintenance of their platform, also if they pay tax, the government used such in developing the society we live in, as everyone of us are direct or indirect beneficiaries being a citizen, the gambling platforms also employ their staffs and pay them.
Thereby creating opportunities for employments and some live to depend on such offers, at the end, money circulates and people have it base on what they have contributed so far, people also spend it on what they value and needed for their own benefits.