I actually know Jonathan Martin's cousin. He went to grad school with an ex-gf of mine.
First of all, people have no idea how unique that man is for an NFL player. His black teammates actually have way more in common with Incognito than they do with Martin. This is one of those rare situations where class trumps race.
Consider the profile of the "average" NFL player, regardless of race. Guy grows up going to public schools, standout athlete, gets recruited by some state school with a reputable football program, gets drafted into the league. Nothing really remarkable about his family, save for maybe another athletic family member give or take.
This is nothing like the background of Jonathan Martin.
JM comes from one of the most prominent African-American families in the US. He has great grandparents that were among the first black graduates of Harvard University, in the early 1900s, a time when few Americans - let alone African-Americans - received a college education. Multiple generations of his family attended Ivy League schools. This is not even common among white Ivy League graduates.
He has a direct pipeline to the White House, Wall Street, you name it. Members of his family are part of the elite and powerful.
Jonathan Martin never attended a public school. His elementary school was one of the top three in the LA area, and for high school, he attended the world-renowned Harvard-Westlake prep school. This school is one of the most well-known feeder schools to the Ivy League. Its educated countless members of the top 1%, including royalty from foreign countries. Its one of a handful of American schools that is part of the
G20 (an exclusive association of exceptional secondary schools around the world). He's never really socialized with people remotely like Incognito or the vast majority of NFL players for that matter.
For university, he attended Stanford (turning down Harvard because Stanford is basically the same caliber academically albeit with a reputable football program).
With his rarefied background, Martin could have easily went into Wall Street or wrote his own ticket. He chose the NFL because he loved the game, but he has never been around the type of guys who play in the NFL. Not even limited contact.
This is different from guys like Richard Sherman, who also attended Stanford, but grew up in COMPTON and attended regular public schools there. So he's used to riff-raff.
Martin simply has nothing in common with most of the guys who play in the league except that he happens to be black, but in name only.
He comes from an honorable family unlike most Americans, so insults to his sister and the like cut much more deeply than it would for most guys. For him, guys in the NFL are practically the dregs of society. That's why it's no big deal for him to call it quits and move on with his life. There's much more in store for him elsewhere whenever he wants it.