True, Warner Brothers doesn't care. But people DO. Not buying it prevents them from getting YOUR money, to which they say "I don't care, that's just one person."
Talking about the issues (what others see as bitching) gets you AND other people to not spend their money. Bitching hits them harder, because you can take customers away from them. Even if it's just one person you convince never to buy microtransactions (unless they're just cosmetics, then go crazy), you are actively showing people that microtransactions are generally inherently bad.
I care about people with gambling addictions not be enabled because they literally can't help themselves.
I care about children not taking their parents credit card/not knowing how much to spend to not be allowed to do so.
I care about depressed people not wasting their money just for that one second "high" you get that makes them happy, because it's taking advantage of their poor outlook.
I could give less of a shit about what the Publisher thinks. I care about people not being taken advantage of.