Corbyn ordered an enquiry at the behest of Jewish members of the party, which was the only thing he could have done - that enquiry found no serious problem
To have ignored demands for an enquiry would have played into the hands of the media and the right wing of the Party
Starmer carried out no enquiry, but has sacked a minister for criticising Israel - that is not only divisive, as has been shown, but it is tantamount to agreeing that criticising Israel is antisemitic - which is, by definition, antisemitic

Tenth and final clause from The Holocaust Remembrance Alliance definition of antisemitism
"Holding Jews collectively responsible for actions of the state of Israel."
If it is antisemitic to criticise Israel, it follows that claiming criticising Israel is antisemitic implies that The Jewish People are responsible for Israel's actions - simples

Starmer's action is antisemitic
Jim