Maybe not logical to us but it’s perfectly logical to a teen who’s out of control which she obviously was. Teen know everything. Teens are invincible. Hippys were into free love and not trusting anyone over 30. They were doing anything and everything to bust the system. So, yeah, chasing sailors would be the wild and crazy thing to do.
Well, as we say in Oz, ‘I don’t know her from a bar of soap’ but I see it most unlikely that she would be out of high school and a month later off to the docks to hunt down black sailors. Too much of the myth rests on SAD being alternatively brilliant, super-intelligent, wayward and for the icing on the cake she posed for erotic photographs - when in fact, we know nothing about her.
Do we?
I don't think we really know if she was out of control or not. There is almost nothing really known about her early life.