The gambling industry in Russia contribute an insignificant percentage of revenue to the Russian economy. Most sanctions on Russia have done little to deter them from continuing the invasion of Ukraine. The oil and gas sector is the mainstay of the Russian economy, hence any form of boycott should be targeted at that sector. Boycotting Russian gambling platforms would only affect the common man in the streets of Russia. Many inhabitants of Russia get their basic needs from these platforms. Boycotting this platforms would only cause hunger and death of the less privileged while the political class would still be living in plenty. Russian gambling site also employs non-Russians around the world. Hence boycotting these platforms can even affect members of this forum negatively.
I would love to be such an influential person to be able to boycott gas and oil from Russia. I'm afraid the boycott of Russian casinos is just all I can do.
This boycott is about reducing the inflow of tax money from profit in casinos. The less tax from casinos reaches Russia's budget, the less money they will have for support the war.
On the other hand - if you boycott a casino - it might affect the individual owner of the casino or handful of members who uses the website and brings revenue to Russian Banks. This might not have much effect on the economy. But - the oil and gas crisis can really put a country in trouble. It's better not to take Russia easy.