On the "democrat" side, Yglesias argues, Ibrahim is clearly just being responsive to democratic pressures inside Malaysia, whose citizenry is itself becoming more and more virulently anti-Israel. This is well-taken. We often use "democracy" as a loving, catch-all term of rainbows, but of course when bad ideologies are popular, they will be well-represented in a democratic context. That's why sometimes "democracy" gives you Hamas. It shouldn't surprise us that in areas where Israel is deeply unpopular, democratic politicians are deeply anti-Israel. Similarly, while Ibrahim's recent forays into Jew-baiting are deeply disturbing, and seemingly flow out of this rise in anti-Israel sentiment, there is nothing suggesting they're anti-democratic.
Turning to "anti-American", though, things are a little more complicated. Matt is certainly correct that this is a nebulous and ambiguous phrase -- particularly given my belief that American interests are constructed and thus are open to contestation: we're allowed to say that we, as a nation, are interested in Israel being treated fairly, if that's what the American people through their elected representatives decide is important to our country. But even from a more standard perspective on American interests, I think Matt is looking through a very narrow lens.
Clearly, though, Malaysia is very far away from Israel and not the kind of country that’s engaged in global power projection. I would think that we would therefore judge the pro-Americanness or not of a Malaysian politician primarily in terms of his attitude toward regional issues in Southeast Asia. Perhaps a “pro-American” Malaysian leader is one who wishes the United States to play a robust security role in the region in order to counterbalance China. Presumably there are some specific issues in the area that we care about. But certainly it would be odd to make Israel the top agenda item during a discussion with Malaysian officials (one striking thing about being in China during the Gaza flotilla raid is that nobody there cared at all) or the main criterion by which we judge a politician.
Without objecting to Matt's point that the US has many interests with regard to Malaysia, simply noting that it is far away from Israel hardly means that the US is entirely uninterested on its position towards the Jewish state. Fanning extremist attitudes in that region is bad for the US on a host of levels, and that can be done by leaders near and far from the region (see also: Hugo Chavez). Malaysia's important role in the OIC also means it has disproportionate impact on how Israel is treated in international fora beyond what one might expect from mere geographic proximity. Using Israel as a scapegoat and focal point for any and all international ailments likewise is a barrier to the US accomplishing its foreign policy goals. The way in which Israel is constructed as the linchpin of all that is evil in wrong is turning it into an organizing point for reactionary movements worldwide, and that is exceedingly dangerous for the US even if we did an entire 180 on our position regarding Israel.
And finally, one would hope that the overt anti-Semitism that Ibrahim and others have engaged in (talking about "Jewish-controlled" organizations pulling the strings of the government) would be something the US would be "interested" in opposing if for no other reason than that we should be interested in insuring that Jews can live and travel safely to any country in the world without fear, and that ideal is threatened by such rhetoric.