And how you define your terms. Please note that I am not defending his point of view, but in his mind, your professor is entirely correct in his statements, because of how he defines his terms.
The professor said that I would kill and die for my beliefs makes me the same as those we are fighting against in Iraq and Afghanistan.
He is correct. But only if you think being in the same category means being the same. Every US soldier, sailor, and airman who ever faced combat was willing to kill, and if necessary die for their beliefs. Every soldier, guerilla fighter and revolutionary of every nation is in that category, men committed to a cause, and willing to do what they deem necessary to see it through.
How about family men (and women) that would kill or die, if necessary to protect their families? They are as committed as it gets.
Does that make them all the same? Exactly the same? Not in my book. There are too many differences for me to think they are all the same, but perhaps, not to your professor. He might be one of those sad individuals that have never found anything in their lives (including their wives and children?) that they considered worth killing, or dying for. Perhaps you should ask him?
Another point of semantics is the term "gun owners". We normally think of that term to mean people like us, who own and keep guns and abide by the lawful conventions of society. But reduced to its broadest possible meaning, anyone who has a gun in their hands is, for the time they hold it, a "gun owner". Not in the usual legal sense, but in the physical sense that if you control something, for the time you control it, you "own" it.
So, using the broadest possible definition, Policemen, soldiers, fanatic Jihadists, sportsmen, Nazi death camp guards, and olympic target shooters, and anyone else who holds a gun for any reason, good or bad, are all gun owners, and apparently in your professors mind they are all equal. Perhaps you should ask him why he holds that attitude as well? Is it ethical for him to consider them all the same because of the tools they use?
As to the question of what you would do if the govt orders us to turn in our guns? Molon Labe, from my cold dead hands, etc., are emotionally charged phrases, and do convey the depth of our feelings, but a better answer (especially considering the audience) might be to calmy, in a rational manner explain that it would be a violation of your constitutionally guaranteed civil rights
(note the phrasing), and that such a clear violation of the US Constitution (the highest law of our land) would mean that government no longer owns your allegience or your obiedence. And that it would be the duty of every citizen to resist such a thing with all necessary means.
Terrorist is a nebulous term, depending much on your point of view. My opinion is that the term is grossly overused.