It seems like if the statement is literal, then it’s self-disproving, since the person cares enough to say that, and the person who they were saying that to cared enough to say whatever they said or did prior. Also the likelihood of no one (as in, no human I guess?) caring about what they had to say seems very low, and chances are a large number of other people probably would care, too.
If the statement isn’t literal but more rhetorical, then I’m not sure what it means, but I suspect it basically just means “I don’t care” (as in the person who says “No one cares” doesn’t care themself and wants to express this in a way that seeks to hold more weight by asserting that all other people feel the same sentiment as them, even though arguably they demonstrably care somewhat if they went out of their way to say that, I guess depending on effort required, or perhaps didn’t care originally but then developed some degree of care as a result of the annoyance they felt at being exposed to something)… or maybe it just means “I don’t like what you said/did” or “I’m annoyed by you”… alternatively it could mean “I think you’re stupid/worthless”, “I disagree with you” or “I don’t want you to speak/speak about this again”, or similar.
Anyhow, what is the most appropriate way to respond to this? It seems like an emotionally charged statement that warrants, perhaps being completely ignored, or maybe a measured response seeking to find some understanding or common ground, though a witty retort could be appropriate if respectful (I don’t believe 2 wrongs make a right, unless the first wrong somewhat necessitates the second, if that makes sense). That said, I’m open to hearing any kind of replies that might be given, regardless of how cordial/civil (or not) they are.
You’re missing a critical distinction.
People can not care about (topic), while caring a lot about (disruptive discussion of (topic)).
The two aren’t mutually exclusive.
It’s like I don’t have a particular opinion about cornflakes, but if you keep waving a box of them in people’s face and hitting them with it, then i’mma ask you to stop.
It can be annoying to have to deal with someone going into excessive detail, making inappropriately-fine distinctions, or taking a strong position on one side or other of an argument that nobody’s making - since in all of those cases, nobody is willing or able to engage with the topic, and it’s just taking up conversation-space with (effectively) a monologue that they find boring and exhausting.
If someone says ‘hey look at that funny-shaped tree’ because it looks like something else, it’s usually worth a ‘heh’ in the moment and you move on.
If you start going into great detail of whether or not it actually counts as a tree, or just infodumping neat tree facts, or start ranting about which genus it properly belongs to despite what some people think… then someone will shut you down with ‘Dude. No one cares’.
What if the tree looked exactly like your face and you failed to recognise it so I obsessively photographed it from all angles & made you gaze at the photos until you agreed with me and said “Huh. Something’s up with that”.?