Who said it was? But it's a fact that Arkansas teams, led by Williamson, won an NCAA title, then played for another, while Georgia teams, led by Wilkins, were a complete non-factor (until they went to FF the year after he left). And that Williamson was far more honored with individual accolades as a college player than Dominique Wilkins was.
Wilkins benefits in this comparison because of his pro career (and because he had a nice, shiny object quality to his game), but I can't see how anyone can argue that he was some transcendent college player. He was a spectacular athlete with huge potential who made some highlight plays on really mediocre teams. So did guys like Mike Mitchell, Ricky Brown, and Jacky Dorsey before Wilkins. What separates Wilkins from them happened in the pros, not college. And actually, the same argument could be made for Charles Barkley, who certainly became something in the pros far beyond what he was in college.
If the subject is "best pros to come out of the SEC", then that's not necessarily the same as "best players in the SEC". Which is really what I'm arguing here.