I get the societal norm angle when we’re talking about armpits/ legs because you can see those. A girl could go to the beach and see all the other women/girls having shaved legs / armpits and feel gross or ugly for being the one with hair there and feel judged because it’s on display.

With pubes though you’re not going to see others so you don’t know the norm or have as much expectations on how a women should look, and other people, besides intimate partners, aren’t going to see yours so you don’t feel as judged.