Leverage for what purpose? To fix reddit? Let reddit die or not die.

Reddit has always come after mirrors and they will easily get courts to take down the instances. Don't forget that prior to the API change they came after pushshift.

Additionally, anyone mirroring reddit on the moral basis that the content is owned by the creators and reddit is an exploitative rentseeker, has an obligation to not become a rentseeker themselves. This means things like ensuring that content that users voluntarily delete is also deleted in the mirrors. Reddit in fact had a large battle with pushshift about this years ago such that pushshift supposedly now only keeps history of moderator and admin edits. I agree with that ethically.

And in many cases you may be legally required to do this. To be clear Reddit made pushshift change to respecting user delete requests because of legal exposure and compliance risks.

Not to mention that you don't really know that anyone intends their content to be mirrored on sites they do not use. Particularly now that Reddit seems to be forcing private subreddits to be open. There's no moral high ground for doing this.