Moe -- I don't think you reaaly understand what's happening here. First, like MJ, Nick Symmonds is free to do Nike commercials ... if they wanted him too. Also, just like MJ, Nick is free to wear his sponsored products WITHIN THE RULES OF HIS SPORT. Just like MJ wore Nike shoes, Nick wears Nike spikes. But just like Nick, MJ was prohibited from wearing a Gatorade billboard on his back by NBA rules.
Also, I can guarantee you that the London meet has sponsors who want their sponsorhip to take center stage, and its probably in their contracts with the meet. Symmonds and Jones are liabilities because they've shown in the past they are willing to ignore the rules of the meet for their own gain, and as such, the meet directors are well within their rights to prohibit them.
If this Nick -- Stop being a baby.