The source of the exchange was Touré's unhappiness with Piers Morgan's interview of Robert Zimmerman - George's brother - the night before, and Touré's subsequent assessment that Morgan, as a Brit, could not understand the depth of pain that Trayvon's killing has brought to America.
I saw the Robert Zimmerman interview, and thought, contra Touré's point and as per Morgan's defense of his interview, that Morgan indeed asked lots of tough questions. My takeaway from the interview was that Robert's defense of his brother was about as credible as Joe Oliver's (George's friend) - which is to say, not very credible at all, with little or no bearing on what actually happened the night that George Zimmerman killed Trayvon. I furthermore disagree with Touré's argument that putting George Zimmerman's lame defenders on the air somehow weakens the case against George - to the contrary, the more information we have, the better our capacity to assess what actually happened, and in the case of Robert Zimmerman's account, its discrepancy with what we can see with our own eyes on the video of George at the police station only weakens the arguments of George's defenders.
As for Touré's disparagement of Morgan's ability to understand America, that's just an ad hominem attack with no bearing on the matter at hand. What counts about Morgan - all that counts - is how he conducted the interview, not his nationality. Once we start going down the road of analyzing arguments based on the nationality of who is making them, we move into dangerous, irrational territory.
Which is not to say that Touré, as a black man in America, does not have every right to a special fury about what happened to Trayvon, and be more furious than Morgan or any white person, of any nationality. But there's a difference between justified fury, and channeling it into an attack on a news anchor, like Piers Morgan, who is just trying to his job, and in fact did it well in this case.