Do you pay taxes? Guess you love Nazis. Pieces of shit are everywhere and it’s not possible to boycott them all. Yes, this game is a luxury. Yes, you can still be a good person if you buy it.
Given Rowling’s existing wealth and influence I think the world is better off with the game than without it. It’s not like this marginal increase in money will allow her to create a disproportionate amount of hate she is not already doing. You are why people make fun of cancel culture. If you want allyship you should pick better battles. It’s possible to be intolerant of intolerance and still purchase this game.
And I say this as someone who never liked Harry Potter and thought the game was average (way too easy except for the very last boss fight).