That Citeh explanation doesn't hold too much weight imo,it's usually a tradition among all clubs that the team does a lap of honor around the pitch to salute the fans one last time during the final home match of the season. I'm sure everyone at the match knew it was the last match at the Etihad this season and as a result,Pelle's last match in charge at home. Plus I'm almost certain there had to have been an announcement made at the end of the match about his farewell speech since they had a whole ceremony and video tribute set up for him.
Just seems like most just didn't give a damn or they're dissapointed with how the season's gone but even then,Pelle had a damn successful run at Citeh. The type of run someone like Wenger would kill for nowadays and only a select few actually cared to show him the respect he deserved,that's cold