Not true, but I'm sure if given the opportunity, many men would sleep with most of the female friends of thiers. Not all at once, or all or them, but as a subconsious question of sex between him and one female friend taken for every female friend.
It should not be all that absurd, but a lot of things which are initially looked for for friendship are the same as we look for a mate. Other situations of friendship debunk this, such as long time friends from childhood or friends you have gotten to know through other friends.