As a motorcyclist, I concur. I'm pretty smooth at getting from zero to road speed without making the passenger seasick. But I can tell by the sounds of the highway, a lot of passengers probably hate motorbikes because of their pilots. Not many manual drivers, even on motorbikes where you'd think they might be more tuned in to their engines, are very good at it.
I asked Google this very question earlier today, and got a great answer.
With the electric motor, when you "step on it" you get a loud droning sound that does not rise with the speed as a driver would expect. This really messes up their perception of the actual acceleration taking place. The progressive nature feels like you're being launched from an elastic band.
By skipping degrees to emulate gear shifting, you get that scooping sound one expects when accelerating.
As for the "roar" part... that's a different topic that probably plays more into nostalgia. Hopefully that's only through the inside speakers, and not audible outside...
But properly calibrated regen braking and accelerator pedal can make normal EV driving approach the engagement of a good ol stick shift.