I think what disturbs me most about it is that deputies, as said friend, are sent out to educate our kids and at the very least they should be thoroughly informed.
Based on my decade in the "Second Amendment" activism community, I can vouch for the fact that the VAST majority of LEOs--even the ones with good intentions and impecable integrity--don't actually know crap about the laws of their jurisdiction beyond basic traffic law.
Few know ANYTHING about gun laws. Few (if any) know about vaping. Many don't know about privacy laws, wiretapping and video recording/photographic in public. Most of them haven't a clue as to the difference between "reasonable suspicion" and "probable cause".
And the SAD thing is that they teach them in the Academies to NEVER say "I don't know". They teach them that if they don't know for sure but have a suspicion that something isn't legal, to just make the stop/issue the cite/make an arrest and the "courts will sort it out. They are also taught that if a citizen challenges them on these misinformed assumptions, they are to escalate IMMEDIATELY, and to assume that anyone who questions their authority is a "hostile suspect" and to treat them with the level of force appropriate to such a person.
It used to be that LEOs were called "peace officers". They were there to keep the peace, and to track down people who were KNOWN to hav already committed crimes and arrest them. They used to be helpful, courteous and friendly.
Now, they are "law enforcement officers" and their main job is to generate revenue by citing as many people for as many violations as they can--regardless of whether or not the people are actually guilty of committing a violation or crime. Now they are TRAINED--in the academies and by the Feds--to view EVERY citizen as a potential terrorist, ESPECIALLY anyone who would dare to question their "authority". And they are trained to NEVER show weakness--and if they don't know the law, to use force, persuasion and intimidation to hold their line even if they might not be right.
I have family in LE. I used to work for the US DOJ as a consultant and researcher so I know this business from the inside, (and LE is a business--make no mistake...) Most of them are good people, and they mean well, but it's becoming increasingly difficult for the good ones to stay in on the force (they get driven out by the corruption), and it's becoming nearly impossible for the good ones to not "turn" because they are surrounded by thugs, cheats, crooks and power-tripping bullies these days.
Sounds like your friend is one of the "good guys". I hope they are successful, but I'd bet dollars to donuts that they won't still be a cop in 5 years if they have ANY integrity or honor...