some people get real mad at "can't" in some contexts but like. they're literally just making up an idea to get mad at, right? for instance, imagine the following conversation:
the song's cool but i can't understand the words
wdym you can't?! of course you can, you just haven't learned french yet
never say "i can't".
i might actually burn your house down
the first person is absolutely right to be mad here. they never made any statement that seriously conveys an absolute incapacity to understand the lyrics of the song. this person has used "i can't" synonymously with "i don't" or some similar phrase, and it's pretty obvious that this is happening. they know that it is possible for them to learn french in order to understand the lyrics of the song, that just wasn't in the parameters of the conversation
this isn't to completely void the second person's claim. it is sometimes true that "i can't" is used for a person to devalue themself on account of some imagined barrier. unfortunately for the "can't"-hater, this is simply not the case too much of the time. in these cases, "can't"-haters are imagining a claim that never existed just to be mad at it
stop saying "stop saying i can't"