It's hard for them to do when they themselves are 99% heretical and deposed also. I bet that you have maybe a dozen bishops throughout the world who would find Bergoglio's promotion of sodomy to be heretical. We only had, what, FOUR of them, who had the courage to put their name to the critique of Amoris Laetitia. That's part of the issue with the Unviersal Acceptance argument. Accepted by whom ... this gaggle of Modernist heretics?
And here's the crux of the issue. If the heretical pope won't defrock heretical bishops, and the heretical bishops won't acknowledge the heresies of the pope, then how is the heresy ever stopped?
For the last 60 years, it seems like the answer is: "It can't be."
Of course, sedes face a similar issue regarding how we can possibly elect a pope.
The Crisis can only be resolved miraculously, IMO.