I can't believe you've never heard of the Americade but if you live outside the US I guess that's not surprising. It used to be called "Aspencade" and was held in Colorado up until it was moved to Lake George, NY. That first year (1985) they still called it "Aspencade" despite there not being any aspens in the Adirondacks. In 1986 it was changed to "Americade" to reflect the change of venue and the fact that it had been dubbed the American Motorcyclists Associations "National Rally" (a title it held for years until the AMA decided to grant that title to other events in later years).
The crowd you mentioned are a later development... people who used Americade as a staging ground before heading off into New Hampshire for Laconia Bike Week. In the early days it wasn't like that at all; in fact the bar owners were disappointed that most of the participants didn't drink. Restaurants, on the other hand, did a BANG UP business. In any event the local and State police are usually there in large numbers enforcing local noise ordinances so its gotten better in recent years. The fact that the event is now TWO weeks before Laconia (as opposed to the one week it used to be) also discourages "that crowd" from using it as a staging area; they're skipping Americade altogether and just going up to New Hampshire now.
The year Zero was there they had quite a queue for demo rides. One person in the Zero Facebook group said he'd never heard of Zero until he saw them at the Americade and one ride on the SR/S was enough to convince him to buy one for himself.
For years before a local Zero dealer brought bikes for demos and the Zero factory just had a static display. Unfortunately, they weren't at the main TourExpo; they were at a different site and you had to look for them. Zero only brought demos that one year mentioned earlier. I was surprised the year they introduced the DSR/X that they only brought static display models and didn't have demos.
Myself, I use Americade and their demo rides as an opportunity to try out bikes I wouldn't normally consider. As such, I've ridden some funky, weird-ass choppers, some trikes, and other models. It was a demo ride on a Suzuki Burgman YEARS ago that convinced me a Maxi Scooter would work in my garage. I've never owned a Burgman but I've had Yamaha and BMW Maxi Scooters since.
In fact, the primary reason MOST people go to Americade is for the demo rides, unlike events such as Daytona, Sturgis or Laconia. By skipping it, Zero is missing out on a big opportunity to attract riders who might never have considered an electric motorcycle or have even HEARD of Zero.