It's possible that all you need to know about Martin Amis is that he writes in his autobiography that when it comes to Israel he thinks "with the blood." A quick bit of googling suggests that this expression comes from D. H. Lawrence (although Kipling's name comes up a lot too). But it is an expression commonly associated with the Nazis, who were big fans of this kind of thinking--not just racism but proudly unthinking racism. It is almost, then, as if Amis were saying something like "I'm a Nazi for Israel" or "I'm as pro-Israel as Hitler was pro-Germany." It's shockingly crass, but the degree to which it is shocking, the degree of crassness, is impressive in a way. Of course he might have been thinking of Lawrence alone, but he ought to have heard the echoes of Hitler too.
Amis's writing typically has this extreme, insensitive quality to it (Dead Babies, anyone?), like a literary version of a Quentin Tarantino film. He got there before Tarantino, so credit where it's due, but after The Sex Pistols and others who also liked to shock. There's a rowdiness about Amis's work that was probably refreshing in the 1970s, but when he tries to get intellectual it all goes horribly wrong.