Why does #$likes-Generic also appear in the list?

The short answer is because #$likes-Generic is a genlPred of itself. How can that be? Look at one of the rules that defines #$genlPreds:

(implies 
       (and 
           (?PRED ?ARG1 ?ARG2) 
           (genlPreds ?PRED ?GENL-PRED)) 
       (?GENL-PRED ?ARG1 ?ARG2))

This says that if PRED holds of some ARG1 and ARG2 and ?PRED is a specialized form of ?GENL-PRED, then GENL-PRED also holds of ARG1 and ARG2. There's nothing to say that PRED and GENL-PRED can't be the same predicate.

By the way, the same holds true for collections using #$genls. This is reminiscent of one of the first things you learn in school about sets: the set {1,2,3} is a subset of the set {1,2,3}.