If a Republican physically attacked a Democrat, or a Democrat a Republican, after one said something with which the other strongly disagreed, would it be any defense for the attacker to say, “He knew perfectly well that I detested his views”? Freedom of expression requires not so much the exercise of self-control in what is said as its exercise in reaction to what is said. I can hardly look at a book these days without taking offense at something that it contains, but if I smash a window in annoyance, the blame is only mine--even if the author knows perfectly well that what he wrote will offend many such as I.

via Freedom of Expression, Without the Expression by Theodore Dalrymple - City Journal.