No, that’s not it.
I post comics and other things sometimes that have to be marked nsfw just because they have the word “shit” in it. I think 13+ year olds are able to handle the word shit.
Shit being unsensored is reasonable, because it also refers to actual poop
Bitch is unsensored because it also refers to a female dog
f*ck is sensored because "f*ck" is another term for s*x.
"It's allowed on sites like reddit"
Reddit also allows porn, and that's not a very good idea for imgflip 💀
But yea, I do think 13yo's can handle words
Bad comparison tho (no offense)