Yet his supporters blame everyone else. To potential floaters, like me and Mrs R, believe me, it aint a great look.
TBF this idea that his supporters think and act monolithically, or to use the stock phrase are "the cult", is perhaps the worst meme of them all.
Corbyn has done loads of things wrong, many of them were identified and pointed out in the 2017 election and were not dealt with this time around. He does not go uncriticised for these faults, even by people who rate him in other areas as even a ten minute attendance at any CLP meeting in the country would show. Policies that eminate from the leadership are challenged too and changed in places (Brexit and 2nd ref being the most obvious), in ways that did not happen before 2015.
However why he retains support is more to do with the belief that he actually probably is the best shot Labour have now, and IMHO it is a rational belief - the opposition in the PLP have still not developed a plausible alternative, nor have they formulated any kind of alternative policy programme. They have cried wolf so many times over deselections (which happened a grand total of 0 times*) and purges (which only happened in 2016, when they did it), and some of their members have behaved in ways that even I never thought was possible (Austin, Woodcock, Lewis and whoever else emerges during the last week backing this Tory government, of all Tory governments) that they are now completely discredited.
Corbyn has also considerably outperformed his predecessors electorally as well, and engaged a lot of people in politics who were not engaged in it before.
* not counting the removal of the likes of Jared O'Mara, Vaz, Kelvin Hopkins and Williamson who were not selected because they'd been suspended from the whip