Gander Mountain review: refusal to legally sell a firearm

At 7:27pm 9/29/14 I stopped by the local Gander Mountain to pick up a trail cam and a pocket knife. I have been in the market for a new rifle for a few years now and after talking to a co worker, who is a retired police officer, about the gun laws in Michigan I decided to go ahead and do some shopping while I was there.
Now I'm a pretty clean cut guy and nothing about the way that I was dressed or presented myself would have thrown up any red flags for someone not to sell me a firearm. I told the man behind the counter that "I was in to buy a trail cam and have been looking to buy another rifle for awhile now. I was wondering what Michigan's state laws are on buying a rifle with an out of state license"? After taking literally two seconds to look at a piece of paper he stated that he "was not allowed to sell me ANY gun that they carried". When asked if this was a state law or company policy he said its "state law". He never asked me what state that I was from.
After buying my things and leaving I decided to do some research on Michigan's state gun laws...
I travel for a living and am pretty clear on what most gun laws are due to the fact that I have bought several firearms in several different states. This particular instance was starting to look a little discriminatory to me due to the fact that he refused to sell me "ANY gun that they carry" when the law clearly states that this is untrue. On the way home I called the manager of the store and politely questioned her about the situation. After I was hung up on once (she said that it was an "accident") she stated that the reason I couldn't buy a rifle from them was "because my state (Oklahoma) was a no sale state" (which is also untrue). I then asked her why he refused to sell me ANY gun without even asking what state I was from? She the stated that he must have thought that I was wanting to buy a handgun with a out of state license.
I had made it very clear, from the beginning, that I was interested in a rifle.
I do realize that I have a southern accent and am curious if all of this was due to the fact that I am not a "local".
Either way this experience has ruined Gander Mountain for me and I will never set foot in another one of their stores, up north or down south.