I would have preferred Joc over Turner myself and I'm sure this just adds to my lor as an Atkins apologetic, but hear me out.
Pederson's last 4 seasons (wRC+)
86, 96, 146, 111
He was projected for a 115 wRC+ this year and is a strict platoon player. Joc was projected for 1.1 WAR, Turner for 1.0 WAR.
What was the probability that Joc Pederson had a good year and outperformed his projections? I suspect it was similar to the probability that Turner did - although perhaps you could argue that Joc's age gave him the advantage. However, as a minimum, I suspect probabilities for Pederson and Turner are a lot closer than people want to admit. You also could factor in that Pederson likely only gives you 425-450 PA's a year, whereas Turner likes gives you 550-600.
Although I would have preferred Pederson (due to him being a lefty and having more power), I don't agree with a suggestion that signing Turner over Pederson was some god awful decision. Those saying that are looking at today's results, not the probabilities when the signings were made.
I agree with Term and Laika that at the end of the day, this decision doesn't have a major impact on the season, but fans will latch onto anything they can these days to feed their internal hatred of the team.