I heard a theory on why society looks down on sluts but praises promiscuous men, and I think it makes a lot of sense.

It's because it's very easy for women to get laid. All they have to do is not be extremely fat, and even then it's much easier for fat women than it is fat men. In most cases, they just have to ask.

Men have to have some combination of being funny, being rich, having good looks, and/or being very fit. Sometimes just one attribute is enough if it is an extreme outlier. Sometimes it is just persistence (taking the shotgun approach of asking everyone will eventually get you laid).

Many of these characteristics are hard to obtain and take a lot of work or a lot of luck, and that's exactly why it's seen as less disreputable than it is for women. We don't praise or respect people for doing easy things, we praise when people do hard things.

Why is it like this? Because men are more motivated by sex than women are. They like to pretend that is not the case, but how could women possibly know what it feels like to be a man or vice versa? All we can do is look at the evidence, and the evidence shows that men are obviously hornier, and generally have lower standards.