The original DeWitt Clause was established by Oracle at     
    the behest of Larry Ellison. Ellison was displeased with 
    a benchmark study done by David DeWitt in 1982, then 
    just an assistant professor, using his new Wisconsin 
    Benchmark, which showed that Oracle's system had poor 
    performance.

It takes a special kind of sicko to take someone you don't like, create a fairly dickish policy to basically restrict free speech/fair comparison of products, then name said dickish policy after the person who was trying to encourage the exact opposite.

See, if it were just "the ellison clause" it would need no further explanation.