I'd have mentioned the camel toes.

When putting out a fire you have to remove either the oxygen, the fuel or the heat. Throwing petrol on it might be fun, but not the best solution.
Perhaps saying
"Do you realise that they're quite a safe form of cycling?" Something like that might give them food for thought. Maybe they'll even ask you why? Perhaps you could even offer them a free ride..
Or something a bit more positive than referring to their bits. They obviously think that you're one anyhow. Why open your gob and remove all doubt.
Many regular bike forum trolls have tried to infer that they're dangerous motor bikes and have some tenuous link to recent tragic accidents. That is clearly and simply not the case. There's never been a better time to educate people on the positive benefits of ebiking.
I think that we've all spent way too long in the dark, listening to the negative ridicule that have almost become believable urban myths. Time to rise up, stand proud and share the facts. Riding safer will keep everyone happy. Pedestrians, trolls, traffic, politicians and all.
When I'm riding my ebike, I'm not at all embarrassed by that fact. Nor will I be made to feel that way. People who pass comment on the street are trolls. Trolls don't like facts. They inconveniently get in the way of personal opinions and urban myths. They tend to put the flames out. Wear a fireman's outfit if you like. Most of the ladies like that.
