They would, but the reason why Corbyn can ignore them is the same reason why he could ignore the 2016 vote of no confidence, and the reason why this notion of tribalism / "dear leader" of yours is nonsense. Corbyn really does have the genuine support of the majority (probably an overwhelming majority) of the party, who after all did usually join Labour because it was a left-wing organization and so actually quite like it to be led by an actual left-wing figure who proposes left-wing policies.
What also helps of course is that the internal opposition to him is completely useless.
I don't think anyone denies that Corbyn is popular with the Labour Party membership. The issue is whether he's popular with the public at large. Maybe you think he does; you have every right to your view, obviously.