When there's a word with 2 meanings that are almost opposites of each other, that's confusing. I think it's good to avoid using words in confusing ways like that.
Steven Pinker wrote about this in detail in The Language Instinct.
https://www.grammarphobia.com/blog/2007/01/i-could-care-less...
When someone says "I literally could care less", everyone listening knows what they mean. There is no confusion and no need to worry about whether they are literally correct.
This is just part of the fun and wonder of the English language.
When I hear someone say "I could care less" when they mean "I couldn't care less" then I tend to understand that they value their words, language, and meaning less than I do mine. They're unintentionally signaling to me that what they're saying isn't necessarily what they mean, and so I factor that into my understanding of, belief in, and reliance upon, whatever they may say.
Most people don't think about linguistics regularly. Their ignorance on a topic doesn't mean they would or would not be passionate about it, had they known more.
But people who say "I could care less" are usually not mistaken. They know full well what they mean, and that the phrase seems to say the opposite of its literal meaning.
It's a great example of irony and sarcasm, both of which have a rich history in English, and probably in most languages.
Pinker has a fine discussion of the phrase in the book I mentioned. I can't do it justice here, but consider how the phrase is spoken. I will use italics to indicate emphasis:
I could care less.
Try saying that out loud a few times with emphasis on the italicized words. You may start to hear the ironic and sarcastic intent.
English would be a much poorer language if we could only use words and phrases in their most literal meaning.
Also consider the context. "I could care less" is used in casual speech, where it's perfectly OK to play with the language and have fun with it.
That is quite different from, say, a manual on how to operate a piece of machinery, or any other kind of technical documentation. There of course you want to be as clear, explicit, and unambiguous as possible.
But I wouldn't judge someone's ability to write a clear technical manual based on their enjoyment of irony in more casual speech or writing.
They know what they mean, but they're not expressing some deep irony or sarcasm. They're just parroting back something they've heard someone else say-- incorrectly.
But yeah, sometimes we just make a mistake.
Haven't we all uttered a malapropism at one time or another?
I love watching a flamingo dance!
Consider the related “it’s possible for me to care less” suggesting a preference exists, but it’s negligible. That’s generally how people mean “I could care less”. Which oddly enough means the literal difference between “I (could/couldn’t) care less.” is practically meaningless.
When someone says "it's literally a printing press" about something that is obviously not a printing press, you know that they are using literally as it has been used for hundreds of years[0]: for strong emphasis.
[0]: https://www.oed.com/view/Entry/109061 definition 1c.
I used to argue the other way too, then one day on a whim I looked it up. I was surprised.