It actually does, because it leaves lurkers with nothing to look at and they start using mother social media sites. How many pictures of vacuums or John Olver is someone going to be amused by while on the toilet before they just go somewhere else?
Social media follows a 90-9-1 rule. 90% of users are lurkers, 9% are commenters, and 1% are content creators.
If you cut down on the amount of time that 90% spends on the site, it has a huge impact on ad revenue. These acts of malicious compliance are a totally legitimate way for the 1% group to continue their strike while making it much harder for Reddit to bring in scabs and forcibly end it.