Depending on the severity, I can even be facing administrative charges of patient abandonment under my state's Administrative Code for standards of care for providers.
Consider it, instead, that the police, as a whole, joined the protest which also had a decent amount of support from the populous.
That's a far cry from one person refusing to do their job with very little (almost none) support from the populous, as your analogy would be.
If it was a single cop refusing to arrest a Nazi for a crime because they agreed with them, that cop would be fired.
Same applies here. If 10 officers misbehave, it is easy to fire them all, as you suggest.
If a majority of the entire police force defects, your only choice is between limiting the scope of the punishment to a few ringleaders vs. basically disbanding the police force and starting a new one from scratch, hoping that you can even recruit enough people to do so; but, in the meantime, the city won't be policed anymore, as the entire institutional memory has been purged.
In most similar cases in history, the authorities opted for a blanket pardon, as it is much less of a headache.
It is not even a new problem. Police is a relatively recent institution, but armies, gendarmes, legions etc. rebelled all the time, and peace usually had to be bought by concessions.
The most significant example I'm aware of is Camden New Jersey.
The city’s crime rate was among the worst in the US. Within nine square miles and among nearly 75,000 residents, there were over 170 open-air drug markets reported in 2013, county officials told CNN. Violent crime abounded. Police corruption was at the core.
Lawsuits filed against the department uncovered that officers routinely planted evidence on suspects, fabricated reports and committed perjury. After the corruption was exposed, courts overturned the convictions of 88 people, the ACLU reported in 2013.
So in 2012, officials voted to completely disband the department – it was beyond reform.
And in 2013, the Camden County Police Department officially began its tenure. No other city of Camden’s size has done anything quite like it.
https://www.cnn.com/2020/06/09/us/disband-police-camden-new-...
When the police start siding with protestors that’s a government problem, not police problem.