You apparently haven't worked in rough enough areas.... i know of coworkers who were assaulted (usually by people under the influence or EDPs), some severely (IE, were unable to complete their shift afterwards, and were out of work for several days), and my partner was assaulted (albeit minorly) in the suburbs.
It happens more than you think (https://duckduckgo.com/?q=paramedic+assaulted&iar=news&ia=news).
As for why it happens? EMS is a known soft target, many laws don't protect EMS personnel (or if they do exist, they aren't enforced), and quite honestly, all too often, there are little to no consequences to pushing around the ambulance people, so people do what they can with without consequence . Although based on news reports the problem of lack of consequences for assaulting EMS is worse outside of the US
Is it weird that working some of the roughest areas of LA/Orange county were also some of the best times I’ve had?