I can't not see it as rudeness, maybe it's acceptable for younger generations tho?
I will ask my 12 y o and see if I get a non-troll answer :D
I think it is maybe partly a performative aloofness, which I sort of associate with adolescence but I see this being done by fully grown adults. I think I would go as far as questioning if this 'friend' liked me if they did this lol.