Anti and his fellow cop buddies in Indiana probably believe the hype their unions and other self-interest organizations spewed to them in training tell them anyone with a permit can now shoot them dead for a traffic stop.
I would wager a guess this is why you were treated this way. I'm shocked at how many police officers are actually ignorant of statutory law.
If you're interested, I could tell you about an attempt by the Placer County Sheriff, the FBI, Roseville Police Department and the ATF to enter a residence where I lived without a search warrant. It had nothing to do with me, they were after the owner of the house who I was simply renting a room from. I just happened to open the door when they knocked. It's a big part of the reason I can't stand LEO's, as a general premise.
That said, I still respect most of them and appreciate the job they do. Main reason I dislike cops? Because they expect civilians to play by the rules while simultaneously thinking they are exempt from the rules and bending them at every chance they get.
Also, you were smart for what you did. I personally would never remove my weapon. I would tell the cop to do it.