When people believe in Magical Intentions they tend to think that when something is done with good intentions then it is good, and they often blind themselves (or at least downplay) the negative consequences. Obviously this is not the way things actually work. The toddler who leans way over the table to pass you something at dinner probably had the very best of intentions, but if in doing so they knock over a vase they have still done more harm than good no matter how much you applaud the effort.
I do not believe in hell, but I still accept that the road to said mythical location is indeed paved with good intentions. When the TSA was created I'm sure many of the people involved intended to keep us safe from terrorists, not to destroy our 4th amendment rights. I have a bunch of other examples I could use, but let's just leave it with the one that most of us can agree on. The bottom line is that results matter. Good intentions are nice and all, but they don't trump results.