It's all part of the "I'm better than you" syndrome. This can manifest itself in so many ways, we've all run into it on many occasions, it's just the way that we humans make ourselves feel better about our poor selves. Find a shop that sells Giant or Schwinn electric bikes, they may be ignorant about other manufacturers, but at least they have shown they have an open mind.
It seems like a lot of folks on these forums that put hubmotors on bikes favor cheap, heavy frames. Well, in the recumbent world, there are no cheap frames. Some are less expensive, some are heavy, but very few are "Walmart cheap". I'd think a crank forward bike would make a great assist bike - strong enough and no tiny seat jammed up your clacker, or maybe a steel framed Sun. Should be able to find an EZsport or something similar at a righteous price. Happy hunting, and remember