I think they’re trying to apply the same logic that’s applied to internet platforms like YouTube, Twitter, etc., where the platform is only non-liable for copyright violations on their platform if they have a good-faith system in place for preventing copyright infringement and responding to DMCA requests. I don’t think this logic should apply to ISPs, frankly the entire internet is far too large of a place to be monitored by any one company for copyright infringement, and I’d rather ISPs be nationalized and treated as public utilities than try to fit them into the same legal framework as social media companies.

That being said, even if the courts decide they should be forced into that same legal framework, ISPs could easily satisfy their legal obligations by simply blocking access to copyrighted content via their DNS service (which can easily be worked around by using an alternative DNS). There’s no legal reason why ISPs would be expected to block individual users from their network, and even if there were, ISPs shouldn’t be allowed to exist anyway, the state (and therefore the people) paid the lion’s-share of the cost to lay all that fiber-optic and copper cable across the country, so the state should own that infrastructure and operate it in the interest of the people (Internet access would be considered a human right and publicly owned ISPs would only have prices high enough to break even, not generate a profit).