Bad cops are often in the job for power, prestige, connections, etc., but even then they have a commitment strong enough to gamble their very lives, every shift. A significant number, though I have no stats, "eat their gun" when caught, whether due to shame or fear of incarceration.
Good cops are generally in the job because they have an intense sense of public service, to help their city, state, country - mankind. When called upon to serve in a situation such as Jan 6th, everything they believe in is put on the line. Imagine how personally they took the blowback! Justice, right before their very eyes was pissed on.
I'm not a suicidal personally type, thank goodness with my history, but I would certainly have turned in my shield after such a day. I just watched it happen on TV, and was greatly affected by the traitors to so many brothers who have died to gain and maintain the constitution of the USA. Their actions did more damage than 911, for it was followed by continued division rather than a coming together in grief.
Instantly shattered faith oftentimes shatters one's will to carry on.