Instapundit and I inhabit separate universes, but he nonetheless did manage to convey in one sentence what I tried to convey in a few meandering paragraphs below:
Sure, you can criticize Israel without being antisemitic. But when you criticize Israel for things you ignore in others, it raises certain doubts.
[as linked by Ted Barlow, who also wonders why Instapundit seems be willfully ignorant of the NRA's inner Freeper]