The section of the rank and file that sabotaged him did so because they are possessed by a vile ideology that virulently opposes any concession by the powerful to the mass of the people. Being unable to befriend any of that metastatic species redounds greatly to Mr Corbyn's credit. They are not "good people".
Now Starmer may not be ideologically committed to the ruthless exploitation of the public like they are, but at the very least he harbours delusions about the possibility of compromising with a right wing, both within his party and in the media, that is implacably and rabidly opposed to any project of positive reform. They will never relent in their shameless calumny and perfidy until Labour's program has been completely neutered.
Now, now. Starmer might not be a militant marxist, but he spent a good chunk of his life fighting for workers' rights in court. He also served faithfully in the shadow cabinet under Corbyn - are you saying that Corbyn chose a "corporate stooge" as his shadow minister, and on the hottest issue of the day at that (brexit)?
One of Corbyn's lackings was that he was unable to make friends in his own party, to the point that half of his own rank & file literally sabotaged him at the last election. By calling good people all sorts of unwarranted names we're only going to see a repeat, and $deity knows this country deserves better than yet another Tory government.