I don't understand what exactly is supposed to be so shockingly "primitive" or illogical about Malcolm's statements. The remarks about the national character of the British and their level of civilization and decency can be interpreted as a reasonable belief that conspiring to assassinate a foreign head of state would be a violation of certain norms that the British government is known to follow consistently in practice, and expected to follow by a broad consensus of the British people -- such consensus being strong enough that it can be considered part of their national character.

Now, one may argue that Malcolm had mistaken beliefs about some of the relevant facts here, but Wittgenstein's reaction looks in any case like a silly tantrum. He also seems to be using the Dark Arts tactic of throwing exalted and self-important rhetoric about general intellectual principles to draw attention away from his petty and unreasonable behavior.