What do you consider slut shaming to be? What are the parameters?

For example, if I'm talking to a guy, I'm into him, but then I stumble upon an online profile of his that is pretty...explicit with a nude up or other sexual photo, etc. Is it slut-shaming to be less attracted or think of him differently?

Or if you want to have sex with someone, but then hear about their sexual activity (cruising, raw anonymous sex), is it weird to lose all interest?

I guess I'm not sure how far being sex positive needs to extend into personal decision making. Of course, treat people like human beings who are no better or worse based on their sex lives. But beyond that, what is fine and what is slut shamey.