We currently cite ArxiV, we cite books out of print, we cite websites, heck we cite 'Mein Kampf' when discussing facism. We cite anything that was used as a source.
Banning citations means either changing the above practice, or banning certain sources from being used by academics. That is sacrificing science for the sake of ideology. We ought to consider sources for their inherent quality, not whether we like their publisher.
I get what you're trying to say here, but this is not about work that has already been done, it is about work that still will be done and to avoid the sharecropping that will inevitably be the result from those citations. By giving ample warning it would be clear that those venues are toxic and that there is a good chance that your work would be better served by seeking an alternative venue for publication.
And then when someone does publish work in that venue, are others doing related research supposed to refuse to acknowledge related published work? That's a pretty serious ethics breach in itself.
Banning citations means either changing the above practice, or banning certain sources from being used by academics. That is sacrificing science for the sake of ideology. We ought to consider sources for their inherent quality, not whether we like their publisher.