No doubt, however, is it really normal for a kindergartener to have that much exposure to anything sexual? Of course, it's likely becoming the new normal, but since having sex in front of kids generally results in them being confused and crying non-stop, the more likely source is the ever-blamed media giant.
My point is, the behaviour doesn't happen because they are not repressed, but rather exposed to something prematurely and then do not repress it. It's not a natural human phase.
At any rate, it's likely harmless, though the 'rape tag' is headed in the wrong direction .-.