Because HE bungled it. Not anybody else. HE had an opportunity most would absolutely kill to be able to have and he took it almost as a joke.
No, I dont sympathize with professional athletes making more to play football in a year or two than I might make in a lifetime, when they alone screw up their opportunity.
Now, a guy gets a freak injury that ends his career? Kevin Everett? Yeah, I'll sympathize with that guy. Not Karlos Williams.
EDIT: I'm not saying that the guy shouldn't get a second chance. Only that I don't feel bad for him.