Better ten million pissed off wannabe protesters, than one dead or wounded President.
If I want to disagree with the President, I can send him an e-mail, a snail mail, a fax or a voice mail. The likelyhood of him personally reading or listening to one of these is probably pretty slim, but no slimmer than the likelyhood of one voice being heard above the din of thousands of protestors.
Happy to have given you a chuckle, but it doesn't make me feel like something special- I'll bet that darn near any rational comment could have you ROFLYAO.
The existance of other avenues of dissent is irrelevent. Americans hold an unalienable and constitutional right to free speech and assembly. Removing them from a public area where others have access purely for their political opinions is an infringement of that right.