Being a drug kingpin is not considered "something relatively small" under US law, as you can see from the sentencing. Being the leader of a large drug operation and ordering hits to protect your business would be considered worse than trying to take out a hit for whatever "personal reasons".

Obviously the hits are a lot messier to prosecute as well with the misconduct of the FBI agents, maybe you could hammer that enough to confuse a jury. But people are commenting like the evidence outright didn't exist - I can only think they have either heard it told second-hand, or are employing motivated reasoning.