I don't get how this is infringing copyright or how they can argue that the company directly aims to damage Blizzard. It's actually in their best interest that Overwatch sells as good as possible.
Also yeah, you can't say they are infringing on your rights and harming your sales when they literally need your game to sell well so they can sell their product and make money. If they were intentionally harming Blizzards sales then they are harming their own sales and that is kind of a stupid thing for a business to do.
Bogus argument detected. Cheating can reduce game popularity without reducing it to zero, so there's still lots of scenarios where Blizzard loses money from the cheat while the cheat company makes some money from it. Think of a parasite weakening the host without killing it outright.