Did anyone give a different reason?
The British government has a long history of being anti-zionist. In the 1920s they sabotaged the agreement between the Jews (both zionist and non-zionist) with the Arabs, and did their best to ignite a Jewish-Arab conflict under their “divide and conquer” strategy. In 1947 and 1948 their whole policy was to help the Arabs win in the hopes that the zionists would be forced to ask the Brits to rescue them, and thereby keep Palestine British (though it was half hearted since by May 1948 they had already been forced out of India when their “let’s get the natives killing each other” strategy failed to result in the natives begging the Brits to stay on as colonial overlords).
And it isn’t surprising that Braverman, whose roots are in South Asia (even if married to a Jew) might not share those traditional British ideas.