I don't have an opinion on this case yet, there is much I want to know first, I don't feel I know enough to form an opinion.
So we have a debate whether it is air fresheners or expired tabs? Personally, I think the air freshener thing is a ridiculous reason to pull someone over. They make them with string and put them in the auto parts areas of stores to hang off of your mirror. I was stopped once and ticketed for having my rear window blocked. I had a back seat full and I guess some of it was above the window--I was helping others move someone and took a load in the car to their new home. I was not happy but at least that made a bit more sense than some little air freshener on a mirror. I have NEVER been pulled over for an air freshener. I don't have one on my mirror now but I sure used to, like many people have. I am sure I probably had my graduation tassel back in the day too, another common one.
As often is the case, we may never know the truth unless body cams with voice tell us what they said he was pulled over for. Maybe it was the plates and then the air freshener was also noted after the stop? And then they found he had a warrant?