I have to disagree with your tactics. College is a time to stick your ground and exchange ideas. If you believe so strongly that it is every American's duty to exercise their rights, you should have stayed and exercised your First Amendment rights. After all, as the minority opinion, that right is there for you more than for anyone else in that classroom. Walking out appears childish and submits to majority opinion that you can not argue your point on their level. It allows them to make such accusations as they did without rebuttal, which in layman terms means they win.
Gun owners should be used to being cast in a negative light these days. Unfortunately, we rarely get an opportunity to represent ourselves in a positive light. Usually when the media cast stones at us, we are represented by some barely literate inbred high-school drop out they pulled out of a bog somewhere in Mississippi. Chances to represent yourself and your opinion are few and fair behind. College is about the only environment on earth where these opprotunities do present themselves on anything resembling a fairly regular basis. When the chance presents itself, every gun owner has a right and a responsibility to be ready and to voice their views.
There is a reason the Second Amendment comes after the First. Self-defense doesn't always involve a firearm. If you want to claim that you are ready to defend yourself, you have to be able to do so with more than a handgun. You have to be ideologically sound enough to make an intelligent argument and to present your ideas. Walking out is more than the waste of a good opportunity to present your views--it is the moral equivalent of claiming the high ground while cowering under the table as a pair of hoodlums ransacks your house.
Being misrepresented is something we have to deal with. There are lots of common misconceptions regarding guns and gun owners these days. Few have much to stand on. It wouldn't take much of a debate to expose these lies as the foolishness they are. As modern liberalism infects out education system, it is common for people to ignore the beginnings of our country. Few liberals want to acknowledge that the "shot heard round the world" was fired when the British attempted to confiscate arms. That this event was the catalyst that conceived our nation, and that our nation was born from a hail of lead musket balls in a cloud of gun powder smoke. Whether you call them freedom fighters, rebels, or terrorists, we owe a lot to those men. And it takes very little thought to clearly distinguish between a terrorist and a freedom fighter. Terrorists kill indiscriminately to inflict maximum psychological damage through fear. I doubt seriously if many IEDs were set off in the streets of Boston or Philadelphia. Most acts of terrorism--church burning, killing and raping of civilians, ect.--were conducted by the British, if you believe the history books.
I'll freely admit that I didn't make as much of my time in college as I could have. I have to mental capacity to have easily gotten my degree, but failed to do so because I placed my priorities in other things--like drinking and skiing. This is a mistake I'll have to live with. But looking back, one thing I am proud of was that during my experience as a junior Political Science major in the 2004 elections was that I embraced every opportunity to express my beliefs. All the time I have spent on these forums and elsewhere educating myself did not go to waste. And I assure you that more priceless than embarrassing a fellow student in front of the entire class, is turning the head and earning the attention and respect of a die-hard liberal professor.
You don't tuck tail and run when you're right. Good guys don't hide. The American spirit does not allow for integrity and morality to retreat in the face of majority opinion. That is what makes this country great. Everyone is guaranteed a voice. The Bill of Rights does not exist to guarantee the right of the majority to speak their views, the right of the majority to worship as they please or petition the government, or the right of the majority to keep and bear arms or be represented in court. Those rights exist for the minority voices. If you truly believe as I do in the duty to know and exercise your rights, next time you'll be as ready to use your First Amendment rights as you claim to be to use your Second Amendment rights.
[steps off soap box]
"...nothing says 'I WILL shoot every last one of you before you have time to reconsider your poor choices in life' like an AK."