Why did people allow feudalism to happen?

People had no choice. If you were born into peasantry or serfism, you were there for life unless you became a priest. You couldn't fight the king or the lords or knights. The kings got a ton of power and no one could do anything to stop it. The only people with enough power to not allow it to happen were the kings and they didn't want it to stop.  It is much like how the 1% in USA is getting way richer and more powerful because we, as the middle class, can't do anything about it.

Because the lords were protecting them from outside attacks in exchange of their labor, which in those times wasnt pretty much if some person is trying to kill your family...

Bob: coke is baby pandas.jim: what? how do you figure that coke is baby pandas? bob: because this book says so.jim: how do we know the book is correct? bob: because it says that coke is baby pandas.jim: how does that prove the book's accuracy? bob: because it's statement involving coke and baby pandas is correct, therefore it is accurate.jim: how do we know that it's correct? bob: because we have concluded that the book is accurate, and therefore the statement is correct.therefore, coke is baby pandas.