It's not a bad comparison. Teachers, bouncers, pediatricians, psychiatrists, people taking care of people with mental disabilities, drug rehab workers, customer service reps,... There's a wide range of professions which will regularly face aggression. And somehow, we don't think any of them should "not accept it" and retaliate.
Cops are THE number one profession who are most likely to face aggression, and it is THEIR job to be well-trained in how to handle it and de-escalate. It is normal and expected that someone who's just had a car accident, or been raped, or been assaulted, or found their spouse in bed with their sibling, or whatever the f you're called over for, is emotional, somewhat more unstable than on average, perhaps panicky,...
If it's not to help calm down and protect the people you meet, I don't understand why you think being a cop is a great job. Carrying a big gun and telling people what to do with impunity is "bully" not "cop".