Anti-semitism is a common charge in discussions of Middle Eastern politics, and although I believe it tends to be used too liberally, there's also good reason for that.
I'm uncomfortable with repeated use of the word "zionist", for instance, not because it isn't a legitimate word both with both historical and current meanings, but because to me it is now hopelessly burdened by white supremacist, William Turneresque ZOG connotations. So even when I feel a given criticism of Israeli policy is entirely reasonable and well-argued, if "zionist" features more than once it gives me the willies.
I also have a big personal problem with crypto-Nazis, and I know very well there are people who pretend that racist fascism isn't at the root of whatever political comment they're making when it totally is. They use code, pretend to be pro-Palestinian human rights in order to get people who would normally spit on their Nazi crap to agree with them. I've seen this kind of shit on discussion boards more than a little and it seriously drives me nuts.
The other side of that coin is the to my mind spurious notion that any criticism of the Israeli government is grounded in hatred of Jews -- something I've seen a lot in the mainstream press and among the punditocracy. This serves more than anything to paint critics (often progressives/liberals/lefties) as anti-semites and therefore easily dismiss their criticisms.
I suppose my perspective hidden among all this blather is that it is essential in these kinds of discussions to eschew sloppy generalizations and conclusion-leaping as much as possible. Even saying something like Isreal is this or Israel is that can be a messy affair because Israel is not a monolith, but a democracy which has seen many governments from different points on the political spectrum. Assuming a positive, detailed discussion is what you're after, of course. That's not always the case and it's not necessarily a bad thing when it isn't.
Confused yet? Good. My work here is done. I'll leave the cogent argumentation to y'all then.
P.S. -
Here's the best post I've ever read on the subject of Israel/Palestine. I know it's only tangential to this thread, but I love it so I can't help but post it again here.