So what I wonder is, are corruption of a minor laws in place to simply protect minors against sick older individuals or are they supposed to give parents a way to put their daughter's boyfriend away?
You're deliberately missing the big picture, kid.
Even if the PA legislature did not specifically intend § 6301 as a means to "put away" teenage horndogs like yourself, there is nothing to prevent the law from being applied to that effect.
Second, the laws of Pennsylvania support the parents' right to exercise control and authority over their minor children. If your girlfriend's folks decide FOR WHATEVER REASON that they don't want you sniffing around their daughter anymore, they can take steps legally to prevent you from seeing her.
It is abundantly clear that you are not asking because you want to understand the law, but rather because you want to test the limits to find how much you can get away with. The wiser course of action would be for you to find a girlfriend your own age, or to leave this particular girl alone until she is 18.