Most women would not consider such an ordinary social interaction to be harassment, but suppose a small fraction do - being perceived or accused of harassment is such a negative thing that it can be a strong deterrent even if there's a low chance of it actually happening.
If you're accused of harassment as a guy, that has huge negative social and career effects that are close to impossible to fight. Everybody turns against you and you're ostracized from your community. It's a big deal.
Of course it's a big deal. I never disagreed with that to begin with. Some people understand ostracism. That's why they don't do the things that cause ostracism.
