Because ICE engines are a robust platform that have pretty much been figured out with an infrastructure to match just about anywhere in the world?

Don't get me wrong, I think batteries/fuel cells are the future, but in some places, ICE is still the only viable option for some while things catch up.

Also a lot of electric motorcycles are stupid expensive for what they are (granted, in this case we're already talking about a company that makes expensive rides, but overall, the high costs hurt adoption).