Notably, it only changes the public charge ground of inadmissibility, not the public charge ground of deportability. See page 56:
So I think people who already have green cards generally don't need to worry about it.
Thanks for the links.
You're right, it's written that they're directed at inadmissibility (not deportability).
However I imagine if a person is inadmissible for a reason, the same reason can easily be used to deny extension/renewal of status or PR green cards, at least during the initial 5 years. So, text not withstanding, it is still a cause for green card holders to be worried that they will also be held to new standards.
They say the rule dates back ages, but back then a (relatively expensive) health insurance was not required. New immigrants were not saddled up with the requirements they're now. People would be admitted merely for being able-bodied/skilled with a chance of employability. Now they can be asked for savings/sponsors, background checks, insurances, just for temporary visas. It's sad because people can get cheap foreign insurance with US coverage, but they're not ACA compliant. I know Europeans can take (rather highly evolved & affordable) medical insurances with them, sometimes upto 8 months as they establish US residency that are valid during their initial job-seeker period. They don't really need public aid. However they won't be accepted as ACA standard, so at the end of the year they would get US penalties anyway! It may be good enough for activation trips though.
It's clear DV people these days are likely to face new rules in the making! Oh well, adventurous times I guess.