Marshawn was also 24 (Percy's age) when Seattle acquired him. If you look up the initial reaction of Buffalo fans to the Lynch deal it's actually eerily similar to how Minnesota fans are reacting now i.e. he's a malcontent and a distraction and it's time for both sides to move on.
At the same time, you won't find anyone who claimed Marshawn didn't give it his all as a competitor. Same with Harvin. Pretty sure that's all that matters to Pete. The rest can be corrected by the right environment as we've already seen.