Any one who is comfortable and secure with themselves shouldnt be overly bothered with a girl who has fucked enough to have some education about what she likes. I will always take a girl who has slept around a little bit over some nervous chick who has only had a few cocks in here life and is boring in bed.
I think one thing a lot of men notice is that a huge percentage of women who claim to be liberated and secure with their sexuality are actually just girls with daddy issues who fuck to feel better about themselves (not implying anything here) rather than actually just fucking around because they want to cum and go. That said, god bless sluts for the joy they bring to the world and the men who can accept/use them for what they are.
To address why men are congratulated for sleeping with many women and women are held to a different standard I think you need to consider the fact that most guys cannot just go out and get some good looking girl to sleep with them. Those who can bring home good looking are admired for it. On the other hand, all a girl really has to do is talk to a guy for a while and she can dictate whether or not they fuck (even is she's pretty unattractive) because a 2 at 10 is a 10 at 2 ( <--- fact of life) and getting laid is easier by comparison...although that is due to the fact that the whole sexual prejudice exists in the first place because most girls like cock as much as most guys like a nice tight snatch.
To use a metaphor which I think is quite appropriate - It is somewhat like a key and a lock. If you had a key that opened many locks then you would have a master key...and that would be pretty fucking cool and rare. On the other hand, if you have a lock that can be opened with many keys, well that's a pretty shitty lock and not exactly something to brag about.