I'm not familiar with USDA inspections so cannot comment on that but I have found this thread fascinating just looking at people's behaviour and language.
Can I play a few things back to you?
"They have gotten a god complex"
"they have extended there self proclaimed authority"
"They have developed... hatred towards people (myself being there main focus because i push back and challenge them when they are not following there regulations"
"Unfortunately our inspectors have "god syndrome"."
"They retaliate any time you challenge them."
Every time you go into an interaction with them, all of the above will be in your mind and probably obvious to the inspector.
I'm not sure what the answer is but I'd love it if you could somehow find a way to clear the air. I bet there are frustrations on "the other side" about peoples' approach to them too. The reality might lie somewhere between how you're both perceiving the situation.
I was talking with someone yesterday about an old employee of mine who has ended up in a pickle with a customer. I always rated this employee but honestly on looking back, the one area she had some problems with was if she took a dislike to the retail customer. There were times I needed to step in and help that relationship, which I did, smoothed it over etc. For all of my slightly gruff demeanour on here, I have the ability to be charming when needed
Anyway, this ex employee has moved onto another site in the group and is now being managed out to retirement sadly because she's faced into another retailer issue where the site have had issues and she's not managed the relationship well. I know this retailer. They can be absolute a***holes. I have no doubt that she's been straight up, honest but probably with her thoughts all over her face that "I don't like you, you're a jumped up little tw** straight out of university who knows f all."
I feel a bit annoyed with myself that I didn't help her get out of this habit in my time managing her but I did support the relationship in that time and unfortunately now her direct line manager is more hands off so has let the problem get too severe. But I'm wondering if something similar is happening here. There are retailers, regulators and customers out there who are absolute knobs. But they still have a huge potential impact on your site so you need to find a way and, unfortunately, as the person with less power in this dynamic, it's incumbent on you to find that way.
A book I read years ago which had a huge impact on my abilities to influence others is called "Influence" by Robert Cialdini. It might be worth reading a summary of it. There are ways to build rapport with people which will help difficult relationships. It doesn't mean that you're not right, that they have a "god complex" or whatever. There are certain kinds of people who are attracted to roles like that who perhaps shouldn't be doing them. But being right that the people are idiots doesn't help your situation, whereas putting effort into that relationship might.
There is a therapy technique in CBT called ABC (it's also used in behaviour change). Antecedents, behaviour, consequences. The way it's used in therapy though is more around trying to break the link between antecedent and behaviour because there's actually another step of a "thought" which puts a layer or spin onto the antecedent.
When you interact with these regulators, you will have them raising things you believe are out of scope. Your thought might be "they're acting like they're gods!" Your behaviour may then be dismissive or rude (unconsciously) which then leads to them getting worse. What if you actively try to change that thought to something more neutral that you could honestly believe, for example, "they're just doing their jobs" or "they're a bit nitpicky but they are thinking about consumers and that's ethical"?
You might find that your relationship starts to change because your internal environment and thoughts about those people start to change...
Good luck whatever you do.