To be blunt, I don't blame them.
There was a price on his head, and while I understand why he would do what he did (though his direct intentions haven't really been made public), and I agree that there are good reasons for what he did; the fact is, he committed a crime.
While we're all basically cheering on what he did, I'm sure that CEO that I don't care enough about to remember his name, had family and friends and stuff who will miss him greatly.
Those people, under the law, are entitled to justice, the same as you or I are entitled to justice when healthcare CEOs deny coverage that directly leads to someone's death. Though, I don't know how much of the latter has ever transpired. Regardless, the fact that we're entitled to our day in court to get justice, so are they.
Provided Luigi is guilty, of course. This fact has yet to be proven in a court of law.
With all that in mind, and the monetary reward for basically turning him in, for someone working a minimum wage job at McDonald's, that's an easy call. You're technically "doing the right thing" by tipping off police to the whereabouts of a suspect in a murder, and you also get a payday for it. Win-win ? I guess?
Personally, I was hoping that, we the people (or at least the US people), would feel so strongly in support of what was done, that we would individually agree unanimously, that we don't turn this person in, and we just carry on. Sure, authorities would keep looking for him because they're paid to, but the general public simply isn't helping them at all with it.
IMO, that would have sent a very public and very clear message to the people in charge that "we the people" do not care about you. We have the power to do these things and suffer no consequences. We have the power that you think you hold. Do the right thing, or you're next.
Alas, not the case. Oh well.