As far as safety goes I’ve seen far more slow riders causing problems then fast ones. Once a guy got frustrated waiting for an opening to cross the road to a particular vendor and just shot across causing a bunch of us to jam on the brakes abruptly. And plenty of times approaching slow riders to pass them on the left with plenty of space they abruptly veer left without looking. Some even had rear view mirrors they didn’t bother checking. So all the emphasis on fast riders is misplaced. No, when you pass 1,000+ riders a day, you do not shout out “on your left” each time. You watch their line and make judgement calls.
But ebikers can be not only dangerous but rude because they did not acquire any experience as they trained up to a faster speed. The vast majority of fast riders are safe and polite. Sure there are some exceptions. And I have not had safety issues with ebikers but etiquette issues when they shout for others to get out of their way. So tacky. Like farting in a pace-line.
But there have been very few ebikes thus far on RAGBRAI. For so few ebikers the issues are disproportionately high. As the numbers increase so will the conflicts. But riders who were fast self propelled riders when younger and now need an ebike are typically no problem. If I ever need an ebike though, that’s when I just hang it up instead.