I don't know if I've ever seen a HOFer get consistently dumped on by his own fanbase as much as Pau has the past 5 years.
Second best player on the team syndrome. See Pippen, Starks, young Kobe, etc.
But really, the majority of the criticism of Pau is baseless. He's been at his most productive when he's in the low post using his quickness against bigger centers, and size against smaller ones, but he's been pushed out to the high post the last two seasons. And yet he's still been very good. Also there's the fact that the Lakers have the biggest fanbase, and thus more people who don't know what they're talking about.