The left generally puts Israel's crimes in the same league as those of other Western countries. In many ways they are: genocide is genocide, apartheid is apartheid. But they are not always the same, and it is tactically inappropriate to amalgamate them.

It would be better from a Palestinian perspective to emphasize the differences between the West and Israel. We abolished apartheid: they didn't. This drives a wedge between Americans and Israelis, which is what is needed.

Here is a particularly clear example of Jewish-led leftist groups trying to amalgamate US and Israeli policies. Jewish Voice for Peace thinks that the state of Arizona's attempts to prevent illegal immigration from Mexico is comparable to Israel's apartheid wall. They are not at all the same. Israel is preventing the original inhabitants of Palestine from getting back in. There is no evidence that most Mexicans originated in Arizona.

"A dramatic IAW event was staged by students from the Arizona chapter of Jewish Voice for Peace at the University of Arizona (UA) and UA migrant rights group No Más Muertes/No More Deaths (NMM), who erected a mock apartheid wall dividing the UA campus in Tucson for a week, drawing a parallel between the wall being built dividing Mexico and the US and the Israeli apartheid wall."

http://dissidentvoice.org/2011/04/bds-breaking-new-barriers/

This is the main reason the American left is so weak on the Israel/Palestine question - white guilt is more use to Jews than it is to Palestinians.