Looking at production rates and isolating 5v5 from PP production is not cherry-picking, it's the only way to assess how a player produced while normalizing for coaches choice. Using total points in a season, points-per-game, etc... is cherry picking because it ignores 5v5 v.s. PP and ice time, especially in situations where you have players like Anderson who were not given a lot of ice time, and no PP time. When people say "production isn't everything, you have to consider context", isolating 5v5 production from PP production is the most impactful and obvious context to needs to be taken into consideration first.
Why would NJ trade him? Probably because they want more PPers, and Leafs want more PKers.