A bit more blunt than what the guy actually said, but I think covers it:
"No, you can't shoot your new AR. Because while it does have a rail, you didn't put any sights on it. And you're not allowed to shoot something without sights.
Also, what drew our attention to this is that you were rapid-firing said rifle. Which is strictly against the rules you read and signed off on.
Refund? Because you're a dumbass who brought in a rifle with no sights? Really?"
This is about the third time I've seen this. One guy had a brand-new AR variant chambered in .30-06, and wanted to try it out. WITHOUT SIGHTS. What the hell are these people thinking?