[Quick Thought]
'Seductiveness' increases the degree to which a person is thought of sexually, whereas 'sexualization' reduces consideration of aspects of a person which aren't sexual. The particular words aren't that important. I'm distinguishing between amplification and reduction to resolve some of the apparent contradictions of "self-sexualization".
Of course it's possible to reduce non-sexual aspects of how you express yourself, but this usually isn't what's happening — that is, people with heightened sexual expression aren't usually expressing less of themselves otherwise — and at any rate doesn't control what others consider of you.
A person could be twerking nude in Time Square, and that in itself wouldn't stop anyone from pondering that person's political perspective or favorite dinosaur.
