Manufactures include the styles for the market the keyboard is intended for, (Arrangers are mainly for mid to oldies) so including the styles you want is a waste of resources for the manufacture as it will not increase sales. (To be honest it would probably put people off as they would say, why should I pay for something I will never use)
As Diki says, the arranger is not designed for the type of music you want, so you need to look elsewhere.

Bill