Well, for one thing because I'd like to know if my threads are a cesspool and to be able to do something about it.
If I have some random obsessive online stalker that is posting the most grotesque crap systematically on all my posts and interfering with everybody else I want to know and I want to report them so this person can get moderated for everybody, not just me, instead of having them scare people off from my threads without my knowledge.
I like how Bluesky handles this. They have a turboblock nuclear button. If you block someone not only do they lose the ability to see your stuff, their posts de-thread everything under them. Nobody can keep going up the chain of their posts to find yours or keep arguing in your thread without your knowledge. With that feature set, absolutely block fast. You're effectively doing moderation there.
Here you can cover your ears, but not everybody else's and you have no control about moderation of any kind unless you own your instance AND the instance of the person you want to moderate. Muting is a last resort to make it not your problem, but not a solution.
People keep saying this. Being able to identify carts is not the same as being able to identify resold carts.
There is no tool to identify resold carts. People can and do travel and move to different countries with their consoles. There can be multiple accounts per console. People can feasibly have two consoles right next to each other connected to different networks and swap carts between them. People can change consoles because they upgraded or because they have multiple consoles in the household. And people can and do resell carts all the time.
And there is no way to differentiate those scenarios even if you can/could track each cart individually.
There could be a record of which consoles have played which carts, but that gives you exactly zero information about how many owners the cart has had.
Switch accounts aren't associated to consoles and physical game entitlements aren't associated to accounts. Any account can be in any console at any time and instantly show in in multiple places and while you could account for travel times it's a pretty pointless thing to do that, to my knowledge, Nintendo is not doing.
What is more likely is that a cart showing up many times at the same time could flag it. Which is what everybody, including the guy who had the problem, is hypothesizing. This has nothing to do with reselling or transfering ownership of the physical game, beyond the fact that buying a used, dumped cart is the only way to end up with a dumped cart without knowing there are potentially thousands of copies of it floating around.