Incognito is a full on, troubled jock with a capital "J". He's all about the hyper male activity and in interviews has often spoken in militaristic, "I got my guy's back" terms when referring to teammates. Add a dash of chemical imbalance issues and you've a potential bully.
Martin is perhaps the complete opposite. He's seems to be everything Incognito is not. Worse, he appears to not have had a clue of how to deal with someone like Incognito as Mike Pouncey has. Martin, too, may have psychological issues that have gone undetected (Asperger's immediately comes to mind as I've firsthand experience with a bullied young man with that particular issue. He is at least as bright as Martin but suffers from a telltale symptom of the handicap: an ability to navigate social and personal interactions)
So, you have a hyper male who identifies a "weakling" who won't stand up for himself in a way that makes sense to him. The solution for handling teammates like Incognito is easy: give the resistance he clearly expects and IN THE WAY Incognito understands it. That is, a brief but violent one among teammates. Guys like Incognito tend to respect that however odd it seems to others on the outside.
Which brings me to this: I would not be the least surprised if Incognito had a weird and unmet expectation of friendship from Martin. Martin appears to not have been willing or even able to interact in the way Incognito is accustomed to.
Incognito isn't a racist and he isn't a bully. He's an unstable jock working in an environment where instability is often a plus.
Martin wasn't bullied and he isn't a victim despite all the psychofem babble of the last few days. He's appears to be a young man out of his depth in an often brutish environment. That he gave Incognito 15K instead of busting a chair on his head tells me something is as psychologically wrong with him as with Incognito. That recordings and text messages of Incognito continue to be made public obviously by Martin indicates indicates he's still not understanding the problem.