They said they would request KYC upon any suspicious activity, and they requested it just immediately after you requested a withdrawal. The amount in question is just a sum up to about a thousand dollars, which does not look very suspicious to me considering the days it took you after you deposited to make the withdrawal request and the amount also deposited.
 
Another reason that could lead to them asking for KYC might be multi-account policies. Is anyone around your neighbourhood or your compound also making use of LeetBet? Their algorithm might pick that on cases of multiple accounts; if there are none, then we should wait for their rep to come and give their own side of the story.