And I've been on plenty of sites using AdSense that permit similar language
That was then. This is now.
Back in the day there was a lot of stuff people got away with on AdSense unless it was manually reported or got a manual review.
Googlebot couldn't crawl AJAX and some other ways that some sites displayed comments, and other content, which allowed them to get away with things. Today, with headless browsers being used to crawl sites, that is no longer the case and I'd suspect eventually those sites that have stop words on the page will get nailed.
Also, just because they have AdSense on the site doesn't mean the site will get banned for having stop words on the page, but the page itself will be blocked from displaying AdSense. If the site in it's entirety is deemed too vile, or violates the T&Cs too much, then it could get a full site block or ban.
The bottom line is a site like that shouldn't have AdSense, find some other advertising for your site and use AdSense on something that doesn't violate the T&Cs.
This really shouldn't come at any big surprise because AdSense T&Cs spell out what's allowed in black and white, assuming it was read in the first place and if so just blatantly ignored which is the reason for most banned sites.
I often equate AdSense to the webmaster equivalent of a "hot plate" which when told not to touch it, people do because they need to prove to themselves it's actually hot and get burned, or in this case banned.
I don't really see anything else we can add here as it's a mess, it violates the T&Cs, there's nothing we can do to fix it or even suggest to fix that isn't already plainly documented by Google that you DO NOT do those things.
For that reason, I think we've exhausted the value of this discussion and I'm closing the thread.
Good luck!