Believe it or not, I agree with that. I hate partisan politics. It shouldn't be a factor but usually is.
I see flag desecration as stupid and extremely disrespectful. It's just something people do to try to get attention. I respect my flag, I display it properly, and I fold it properly when it isn't being flown.
I personally do have a problem with others threatening violence simply because they don't agree with someone else's opinion. I see it as hypocritical, sophomoric, and frankly, an assault to what the Constitution stands for.
Express your opinion, do it proudly and loudly if you must, but as you said, the moment you or anyone brings violence into something, your cause becomes weakened, and it must be understood that freedom of speech applies to all of us, not just those who agree with us.