If you play for Man United or are British you can do whatever you want and get off scot-free.
FA's method of thinking:
Non Brits
Robert Huth punches a Fulham player- BAN!
Maroune Fellaini headbutts Shawcross- BAN!
Luis Suarez bites Ivanovic- BAN!
Brits
Calum McManaman tackle of death on Newcastle player- Nothing malicious here.
Jonny Evans punches a West Brom player- Nothing malicious here.