If you want to go by 1997 stats:
https://www.bls.gov/opub/mlr/cwc/dangerous-jobs.pdfPolice officers have massively less risk of dying than fishers, pilots, truck drivers, farmers, metalworkers, cab drivers...
If you want to go by 2017, it's not put as plainly, but check out the incidence rate:
https://www.bls.gov/iif/oshsum.htm#17Supplemental_News_Release_TablesSNR05, detailed industry breakdown of injury cases. Second column gives the best indication of incident rate; percent relative to standard errors, from what I can tell means that it measures more how many people have jobs like that. So a rarer job, one person getting injured is going to have a bigger effect on the statistics even when it isn't as major. You can include them if you want, but then
photofinishing is six times as dangerous as being a cop. Second column, police and related fields have a rate at about 5-7, the most dangerous being those actually in corrective institutions. Sure, that's worse than a lot of jobs, but you're more likely to be injured at a hospital, skiiing facility, as a vet, a
courier... You don't hear any of them cracking under the pressure. You especially don't hear about them regularly covering for one another, and they aren't the ones equipped with bulletproof vests and sidearms.
Generally speaking, if a cop's been so affected by dealing with the 'worst of humanity' that they assume the worst of even they innocent and start resorting to violence from the get-go, they should quit. Protecting the innocent should be more important than wreaking bloody vengeance on the guilty, particularly with how much time they spend on non-violent misdemeanours. If they can't handle potentially risking their life, they should've gone into a different field. That's like a pilot complaining it's too high.
Do they face violence? Sure, but not disproportionately, and it's still no excuse. At a certain point you end up with a system predominantly composed of violent cops and enablers and there's no real system in place to deal with it. That's not even getting onto the likes of:
http://s3.documentcloud.org/documents/402521/doc-26-white-supremacist-infiltration.pdf