In fairness to Franky's character, I feel like he only did that cause he felt she was someone useless, not just cause she was a girl. I can't see Franky trying that kind of thing on say, Robin or Nami (even if they were his enemies). Heck he seems pretty chill towards the sisters that followed him around if I recall correctly.
That being said, I think the joke was overdone in poor taste by including the part about kissing the girl unwillingly and then telling her to shut up. It came across sexist, and unfortunately Oda does not have the greatest track record in regards to sexism. Had he left that specific part out, it obviously would have gone over much better.
I really think Oda is unfortunately working on a trope of machismo that we often see in older TV shows and movies (and some new ones too). Where the "teenage girl" falls for the "older experienced guy" over something like a kiss. And the older guy brushes her off.
An unfortunate instance of a joke crossing into territory unapologetically, and made even more unfortunate by the fact Oda does seem to have a sexist tendancy.
Why is it so much different than say Hancock or Nami brushing off and abusing every male that takes an interest in them? I guess I agree that Oda seems sexist with a lot of things especially when it comes to fanservice? But why is this instance so much different than all those instances? Nobody seems to take offense to all those sexist things when it comes to males.