I have a friend that calls proudly calls herself a slut, because well, she gets with a lot of dudes and likes it. Slut usually has a negative connotation but not always.. it's all in how its used.
Also:
"Of course that's negative

There is nothing positive about dressing slutty because it publicly insinuates promiscuity and willing temporary sexual appetite."
I think that's very positive. I like slutty girls because I don't have to work as hard, it's just a matter of perspective. Again, it's about how the word is being used. If you tell a girl, "You are a fucking slut!!" .. yeah, she might take offense. But what about if two girls are gossiping back and forth and one of them mentions how she slept with Jimmy and is met with "Oh my gawwwd, you're such a slut!".. I doubt she would take offense.
Language isn't black and white. It's in a state of constant flux. Every definition is interpreted differently by different people. And even inside someone's head, an individual's understanding of a word will change over time. No two people are going to have the exact same definition in their mind for a word, because of their different histories and experiences. Even with your example, 'slut' generally has a negative connotation because of societal influence. To me, a slut is just a girl that isn't afraid to sleep with dudes. I like that, and there are other people that think similarly.
More importantly though is intent. If a person says a word that is generally viewed as 'bad', but means no harm by it, why would you take offense lol.
Anyways I gtg I hope I explained my position a little more clearly.