His justification is that he is trying to rebuilt confidence with the Jewish community, and their responses to this are certainly positive, but one wonders if the opportunity to remove one of Corbyn's favoured ones was too good to miss - but that may not play well with sections of his own party.
Perhaps too, and I may be wrong, Starmer wants to be decisive here so as to expose Boris the Liar's reluctance to deal with Jenrick on a similar basis.
Time to get some popcorn in.