I gotta say, some of this conversation really doesn't square with my experience walking and biking in the Boston area. I see bikers as overwhelmingly mindful and courteous, and I'm not sure what common problems other people are seeing on the streets.
Absolutely, I've seen aggressive bikers going too fast or too close to pedestrians. I have no problem calling those people out as jackasses. But since some of you are bringing it up, I realize I haven't actually seen that in a while. It seems like there's been a culture shift over a couple of decades, maybe from sport biking to more casual and commuting biking. But that's just a guess. Now, when the esplanade is crowded, I see bikers go slow or just walk their bikes. If someone is slow in the bike lane, faster bikers will slow down and wait to pass safely. I regularly walk and bike through a slightly messy intersection where it's hard to see all traffic. Bikes go slow and are ready to brake for pedestrians. A couple times a bike has gotten close as I'm walking, but everyone is watching out for each other, and we've had quick chats of roughly "Sorry--No, you're good---after you." This is my regular experience with bikers.
E-bikes I think usually are technically limited to 20mph, which is faster than I normally ride, so I notice them passing me, never with any issue. I also can't remember any time that's been an issue for me as a pedestrian. I see motorcycles and mopeds in the bike lane, and that does seem to be getting worse. They're a lot heavier, faster, and more dangerous, so I wouldn't mind better enforcement to keep them out of bike lanes. Honestly though, our bike lanes are so under capacity, I haven't really seen any problems yet. But it'd be better to fix that now.
Because of this thread, last night I specifically walked around some popular bike routes in Cambridge during rush hour. Some streets have good bike infrastructure, some have bad, some have none. I am reporting back absolutely zero issues from bikers. No speed demons, no close calls, no yelling at pedestrians, no mopeds, no motorcycles. Bikers passed each other safely and stopped for pedestrians. I didn't even hear any menacing bike bells. What a wonderful world it must be when bike bells sound aggressive, because what I did hear was lots of cars blasting their 100 decibel air horns at pedestrians, bikers, and other drivers. I saw cars speed through intersections even as people were clearly trying to get through crosswalks. I saw cars running red lights, even when they couldn't fit through the intersection, so they'd just block crosswalks or a bike turn lane. I saw someone stop his car in the middle of traffic, turn on his hazards, and leave. And multiple times I heard tires screeching, because a lot of people seemed to be flooring it any second they could.
This is just my experience, and maybe y'all encounter a lot more aggressive and dangerous bikers than I do. But it seems like nearly a non-issue, especially compared to all the other culturally ingrained, anti-social behavior on the streets.