I would not use Russian casinos. First of all, I think if I gamble on Russian casinos and lose, then at some point I indirectly support the Russia against the Ukraine because the profit that casino makes goes into Russians budget and funds their soldiers.
Look on a situation from different angle. Try not to lose, but instead make Russian gambling platform go bankrupt. With it, you will reduce amount of tax paid and reduce war funding. How do you like that ? Would you support the movement aimed to bankrupt Russian gabling platforms? Or lets hire Ocean and his friends to rob their safes?
You see, all these boycotts, sanctions, rallies, bans or leaving Russian market does not work so far. This situations between Russia and Ukraine must be settled on a different level.
The bans and sanctions,not the gambling ones though are working quite well I would say as maybe they are not being effective to the Russian government officials but they surely are devastating to the normal civil population in Russia,give it a bit of time like 2-3 more months and pretty sure Russians will be extremely poor,I would put them in the same league as North Korea,for their civil population.
Rage also has come from many Russian oligarchs which had their asset frozen and now they are completely against the war,as I said give it a bit more time and everything is working well.