So if the police are called to investigate a crime, such as an assault or say a bank robbery. They should allow anyone on the scene to be armed while they figure out who the bad guys are? I hope your kidding. Police can temporarily detain you and disarm you without violating your right to carry if they are investigating a possible crime.
I would agree with you if you were simply walking down the street with a rifle in a sling on your back. But at the scene of a crime and the rifle in your hands with police pointing guns at you then its time to put the gun down and talk about your rights afterwards.
You have identified probable cause and yes, I agree that if there is probable cause then they can order you to disarm.
What was the probable cause in this situation? Two guys arguing is not illegal. Bearing a long gun is not illegal. What was the illegal activity that gave them probable cause that a crime was committed. No crime was ever mentioned in the article.