Hmm, yes but the "democracy" that matters is that exercised at a general election. Corbyn was shoved into the position he is in now largely by people with little or no connection to the Labour Party beyond a sudden impulse to pay a nominal fee.
No one, however, that I am aware of is suggesting that he was not elected "fairly and squarely". If he WAS any sort of a threat to Mrs Deathmask and her party I suspect there would be a lot more complaining from that quarter. It is the most telling reflection of his "leadership" that they largely ignore him.