Let's phrase it a different way. For a lot of centrists, liberals, Guardian columnists, etc their understanding of politics is that it is driven by superficial presentation. Hence the idea that people loved Corbyn because he was a magic-grandpa.
In reality a huge chunk of Corbyn supporters would have voted for a mannequin holding the policies they wanted… the person of Corbyn was pretty unimportant. In fact one of the problems for the whole movement is that through no deliberate choice, it stumbled upon a fairly poor choice of leader as its figure-head. McDonnell would never have been able to get on the ballot in 2015 —he wasn't seen as harmless by fellow Labour MPs — but I suspect he'd have been a more ruthless leader.
Whereas the people most keen on Starmer are entirely concerned about HIS qualities as a person. HE is competent, HE appears electable, HE appears prime-ministerial, HE is forensic. It's entirely about the superficial presentation rather than what changes he could bring about or what they want to see. The centre has no vision and it shows.