They discussed "punitive measures" because a service that exists on a ton of platforms outside of iOS didn't want to give 30% of all subscription costs through iOS directly to Apple. If Netflix was just something that existed on iOS that'd be one thing, but a Netflix subscription is something people use on their TVs, laptops, etc. So a user who signs up through iOS, but primarily watches Netflix on their TV, which is probably pretty common among subscribers, is still only letting Netflix get a little over 2/3rds of the sub cost. Doesn't matter if they only used the iOS app once.
If Apple was actively promoting the Netflix app, have Netflix pay directly for those ads if they wish to. If not, remove the promotions and Netflix would have no business complaining about it. But taking just shy of 1/3 of their money, even for subscribers who don't primarily use the iOS app, isn't the way to get that promoting paid for.