It has little to do with nationality, and everything to do with a guy who was too impatient to wait for a title shot in his own division and now that that has fallen through he wants to cut in yet another line to return to his original spot even though the division has clearly moved on without him.
It's been three years since he's earned his "promised" title shot and while I don't wish to see Grant bumped from his title shot I see no reason why Pettis shouldn't be on his home-town card. Also I don't feel it's right to blame any of the fighters who were willing to drop down to face Aldo (Florian, Edgar, Pettis) as the FW contenders have failed to prove their legitimacy. Three of the last four fighters, Josh Grispi, Mark Hominick, and Manny Gamburyan have a combined UFC record of 2-10.
If he wants a short camp he should have that right especially considering both what he's been through and what he brings to the table.