In my little part of New England, crap was a word meaning junk or stuff. My mother often said to us, pick up your crap. We are now cleaning out my mother's home of sixty years and my sister often refers to 'our mother's crap.' (I don't, however, as I don't like thinking of my mother's belongings as junk.)
However, when I started teaching and would say to my students, perhaps in a lab situation: 'Please remove all this crap from the lab area...' many of them would say, 'That's a bad word, Mrs. M. You shouldn't say it.'
Some time during my lifetime, at least in New England, the word 'crap' became synonymous with shit. (I missed the day when we all agreed to this change.)
The way words are used or defined can change like that - 'snaps fingers' - or so it seems.
My little grandson has also told me that 'crap' is a bad word.
