We don't like this, either. (Damn, we're picky!)
There is something off-putting about a man who brings up marriage and children during the first weeks of courtship, who discusses adjoining burial plots on the first date, or who professes undying love with lightning speed.
A human door mat is neither amusing nor attractive. And we all know (too well) that a man who is too intense too soon, has no staying power; he is in love with love and not with us.
Girls have more to lose and tend to be more cautious in the mating game. Nature dictates that girls get pregnant, which makes the mating ritual a serious responsibility to females.