There are enough questionable things in religions (and, indeed, in any area of life) to make all of them fair game for criticism. The art is knowing what to criticize, and what approach to take.
I generally stay away from ad hominem comments simply because it's much more fun to tear an argument to shreds. Most of my aggression goes into attacking the "I know I have truth!" position, simply because it seems premature, arrogant and naïve all at the same time. Under those conditions, getting a dialogue going at all I count as a victory. |