Convenience.
Sadly it is something far fewer people are willing to give up than any of the above.

They (probably) aren’t trying to be rude, they are just happy to have an answer they can give quickly and appear helpful. They are oblivious to existing conversations or the communication processing talents of others.

Pathetic but cute. Aw, isn’t that baby 3 legged frog just shlarmle.

https://tildes.net/ is still quite active and while the interface is similar to old reddit the focus is more on discussions than sharing links.

I like to try and combine these to see what kind of reactions I get.
The cream rises to who you know.
The squeaky wheel gets hammered down.
He who laughs last, comes around.
Great minds killed the cat!

STRIKE THE EARTH!!