Agreed. He willingly engaged with the alleged hitman (which ended up being the FBI contact). He didn't need to do anything or not have the thought to murder others cross his mind.
In hindsight, the prosecution probably wished they didn't do that, since they are said to have had overwhelming evidence and proof, and there is even a Wired article about chat logs pertaining to DPR seeking services, but those are the breaks! If you don't do your due diligence, criminals can be let off on a technicality too!
They absolutely do that all the freaking time. Especially when other convictions already result in a long sentence.
Prosecutors have limited bandwidth, and just wasting time adding one more life imprisonment on top of a life imprisonment is not helpful.