In politics, everything is seen as a potential weapon. The question is always how best to use it. If Christie pardons him now, he stands alone. If he waits until the new Congress is sworn in, he's seen as supporting the new wave of conservatism, and can use that to start a campaign. In the mean time, he lets the guy rot and calls it careful thought about upholding the law. And if he never pardons him, it's because he's protecting the safety of the people of New Jersey, and the political winds don't support a pardon helping him run for higher office.
The actual guy in jail, and the actual obscene law he's jailed under, do not matter at all. To even bring these issues up would just get a laugh from Christie at your naivete.
You’re the naive one. He’ll pardon him before Christmas or not at all.