I do not care about "moderator's discretion". However if you truly want that to be a rule then that should be its own separate rule. Rule 7. But this isn't about "moderator's discretion". This is how rule 1 talks about "low quality" content in a completely vague matter that lends itself to be used as mostly as "moderator's discretion". That's not how rules are supposed to be.
It doesn't help that the image of what quality standards are set on reddit are based on the core principles of reddit leads to a lot of people saying "but I thought our votes were what count" but the entire mod team gladly jumps on that point but saying "no no, reddit doesn't work very well". Throw "moderator's discretion" + vague rule 1A into the mix and you will have this scenario keep replaying until the end of time. Sounds fun.
All I'm saying is that if you want the precious "moderator's discretion" then it should be its own separate rule and then make rule 1 as clear as possible to disallow scenarios like the above or the current scenario from happening again. Clarify and define what "low quality" means. Content policies aren't impossible, thousands of sites do it. It's not some amazingly difficult task to be more clear than the 100% vague way the current rule is set up.
If you want a starting point, just define "low effort", "meme", and "repost". It'll take some amount discussion to see if you guys have common definitions, rip those common definitions out, and then communicate said definitions and guidelines with your users. The end result of that will be a clearer ruleset that wouldn't lend to a lot of situations of people complaining that "popular post X was removed". You already do this with everything else, why can't you do it with what you deem as quality? Surely you have multiple exemplary posts of both good and bad quality.
It doesn't have to be 100% clear-cut 30 pages worth of definitions and legalese. It just has to be some human text guidelines that will aid posters in what these things are. Seriously starting to feel like a broken record.