The Stop Killing games campaign is an EU petition to prevent game developers from making games that people bought unplayable, for example by turning off the servers of always-online games.
Pirate Software is a youtuber and game developer who made several videos criticizing the campaign. He thinks it's unreasonable to expect game developers to do this and also asserts that people who purchase games don't own them. His videos supposedly had a measurable negative impact on the petition, which at this point looks like it might fail. Combined with the fact that he often acted quite rude and arrogant towards supporters of the campaign, he is now quite unpopular among them.