Chad Pennington was tolerated for 7 seasons in which he only played 49 of a possible 112 games, was woefully inconsistent, and played scared in big spots. All of this with a Hall of Fame RB, a Top 5 OL, and a consistent set of WR's in each of the seasons he actually played. All the offensive support in the world, did nothing with it.
Mark Sanchez isn't tolerated after 3˝ seasons in which he has played every game possible, won more playoff games than any QB in Jets history, played big in big spots. All of this with a weak carpetbagging receiving corps that he never had a chance to bond with, and a running game and OL that went from Top 5 to Bottom 5 due to neglect from his head coach and his GM.
People cried when Chad was shown the door, some would throw a parade if Mark was shown the door. Chad was given tons of support and did nothing, Mark was given no support and had great success. Chad couldn't make all the throws and was a cripple. Mark can make all the throws and is a rock. What a world.