I actually think it's the public thing that specifically makes it bad. The private thing is an issue, but only because saying things in private makes you more likely to say/do related things in public.

This ties in with my issue with the Hanson and Katja Grace articles. Grace and Hanson seem to be approaching the issue from a single metric - guys treating specific women like sex objects and interacting with them with that mindset. When I think a bigger problem (in a torture vs dust specks sense) is all the little comments guys will make that belittle women in their daily life.

I work in an animation studio. For a while I was in a room with 4 guys and 1 girl. The guys had a raunchy sense of humor and with some frequency, joked about things like rape. I never got to actually talk to the girl about it but my sense was that she was uncomfortable, but pretended not to be. (She'd laugh at the jokes, but occasionally I saw her grimace in a way that didn't look too amused)

She left the company eventually. Now I'm in a room with just a few guys. The sexist comments have gone up dramatically. I know the guys are joking, but I also suspect that they've internalized some of the things they say. (For example, in discussing his romantic partner, one guy says on occasion "seriously, I think girls are just crazy." I think he's only half joking, and that his perception of the girls he's been involved with are warped by the portrayal of girls, both in media and in the way he and his friends talk about them).