I think the big reason for this is most dealers know there's little maintenance cost on EVs, which is where they make their money. With our Nissan Leaf, it's a struggle finding a dealer that even has an EV mechanic, and the ones that don't won't touch it if they don't have one.
With that said though, I've found that sales not knowing anything about the cars they sell to be the trend of late. Even with ICE cars I've bought lately, the sales people have known virtually nothing about the car that I couldn't read on the sticker.