On one level it's easy to side with the offended neighbors in this
story about a couple who hanged a soldier in effigy from their house with a sign originally reading "Your tax dollars at work." But offense is always taken, never given. Not only does that couple have the right to express themselves, but I think the neighbors should be glad they did so.
At least two positive things could come of this. One, this couple has self-identified themselves as knee-jerk leftwing morons with a scissor-like grip on the lessons of history. How grateful should one be that, instead of harboring doubts about whether one's neighbor is capable of rational thought, the neighbor kindly removes all doubt? Secondly, the most appropriate response to "offensive" speech is
more speech. There's no way anybody could now object if everybody else on the street chose to run up a giant US flag.