Interestingly pedestrians accidents go down when bike paths were installed on streets in NYC. Bike paths are closer and have less protection for pedestrians than car lanes so it is interesting that bicycles make it so much safer to be a pedestrian.
Because of how infrastructure is built you experience bicycles a lot closer and therefore they might feel more dangerous than cars. When you stop to think of it it is not strange, but when it comes to bicycles there is always someone who forget.
And some pedestrians are maniacs, but most of the time only are a danger to themselves. OTOH I have crashed into a lamppost from a pedestrian suddenly stepping into a bike lane from behind a utilities box.
I think we should assume that stupidity is evenly distributed and mode of transport doesn't affect it much, just the results.
Momentum is probably more of a correlation than mode of transport. Real world experience: hit by a bike versus hit by a moped, each time on a “vehicle free” footpath. One was not like the other.
It works the other way. Cyclists think all drivers are maniacs for similar reasons.