People lie. This isn't a male or female thing, it a human thing
But not a mature men one?
This is similar to gossip and there is an entire topic on gossip I've made.
Often gossiping is a way to boost a person or a groups status, discrediting others at the eyes of someone. Doing this they convince others that they are better.
They do it mostly to increase their status and get unearned status and resources from the group.
Men gossip with women about other men to remove competition. They know that they can't compete with value so they spread lies.
But when they are in relationship they continue gossiping because these naive stupid women who believe in their lies actually love drama and feeling of power that comes with gossiping and talking bad of others.
Women don't lie. Women LOVE to lie.
The real question is: Are there any sane women out there who realize they are liars and can rationalize that lying or being in a group of people to talk badly about others does not increase their status but actually lowers it?