The only real in-game purchase in Counter-Strike is the game itself to gain access to the ranking system. The skins are a superfluous add-on.

They knowingly profit from gamblers if you will but gamblers are going to gamble.

The gamblers were offered e-sport or gambling and they chose the latter.

You could use Robinhood to build up a growth portfolio starting from a handful of dollars or you could use it to buy 0DTE OTM options on credit. Guess which one the gamblers chose.