If guys on his team want to be ticked off at someone for a season ending prematurely, Fletcher Cox is not the place to start. I know Jason Peters deserves a lot of credit for slowing Khalil Mack in the wildcard round, but he's aging and there were times that he didn't look so sharp earlier in the year. Yeah, he recovered from a major knee injury he suffered in the 2017 season and it took some time to get rolling. Regardless, Cox has overtaken him as the best player on the team.
Even a casual observer should have clearly seen how the game changed as soon as Cox was injured during that fake punt. As soon as Cox was off the field, the Saints offense started to roll. As soon as Cox returned, the Saints saw their promising drive stall immediately when Cox forced a holding call on his first snap back and either sacked or at least hurried Brees into a bad throw on the next play.
Fletcher Cox is the key to that whole defense.
Being "ticked off" at Fletcher Cox when Cox is one of the primary reasons the Eagles are as good as they are would make no sense.