Because Sulaiman is a fat piece of crap. At press conferences you'll always catch him eating something, one minute he's eating a double cheese burger with extra bacon, and the next he's eating a bucket of fried chicken....i think the cholesterol has taken a toll on Sulaiman's common senses.
Because the WBC picks the fighters that they want to give their belts to, and if someone else wins it, they just strip them.
Case in point: Sergio Martinez stripped twice by the WBC in 10 months of both the 154 and 160 belts, after the collected all the sanctioning fees of course.