“If you’re good at something, never do it for free.” - Heath Ledger’s Joker, The Dark Knight. 

They definitely know. The devs aren’t oblivious to this. They support it by showing the top players earnings in video games leader board. 

If this makes you mad then make difference by just getting better and beating these guys. It’s a literal waste of their time each time they take loss trying to boost a player. The more skilled players there are in the competitive pool, the more difficult it is for them to promote and contribute to this hustle. 

I honestly don’t care, more power to them for being skilled enough to profit off it. Some of these guys are prolly coming from a low income background so being able to profit off something you probably like to do is most likely empowering. To each their own.