It might be just socks- but it is also the automatic assumption that the responsibility for another adult's "personal care" lies with somebody else. "Picking up socks with the other shopping" is one thing-"He would look like a tramp if I didn't buy his clothes" is something else.
And the undeniable fact is that it is always women who take this sort of responsibility for men. And the fact that people think it's prefectly normal shows how many of these infantilized men there are. It all ties in with "oh, he can't cook" "he doesn't see dirt"" it's easier to do all the housework myself" "he's very good,he helps me with the baby a lot"
We're talking about adults who hold down jobs, and tasks that aren't rocket science.........