They are the ones that are not being consistent.
Either sex matters or it doesn't.
To me there is no difference between someone saying they wouldn't marry a slut who had slept with more than 10 guys than saying they wouldn't marry someone who had slept with anyone.
The principle is the same, only the number tolerated differs.
Putting a number on your partners having sex, makes no sense to me. Suppose a women was widowed twice, and had 2 kids from each marriage. Does that make a difference? What if she had no children and was never married? I guess, to each his own.