Find an archived version or just don't post paywalled articles. It's true that most people don't read the article before commenting and just go by the headline. But we can't have discussion the argument of the article if we can't read it.
Not at all as far as I'm aware. There's no mention of paywalled content, or archive links, anywhere in the TOS or in any other guideline or policy. I'd guess that it would be against rules to post an article or content that must be explicitly purchased, with a subscription, for example. As it would count as linking to piracy. But in this specific case, where the article is walled by making an account, it's fine in my opinion. It's a gray area in the worst case. This is why most communities encourage posters to post a freely available article when posting news. And if it's something inaccessible without paying for it, just don't post it at all, or make a text post or post an article about the thing. I mean, piped links are encouraged, and that's a similar thing.
It was an announcement a few months back, iirc. They also told people to stop posting entire articles in the comments and post itself (which I used to do)
Just scrolled all the way the whole last years of the lemmyworld announcements community and there's nothing on it.
Are you sure you're not confusing a specific community policy with the instance policy? I can see how posting an entire article in the post body or comment could be problematic, as it could be misconstrued as copyright infringement. But removing ads and circumventing user data mining is an entirely different ethics discussion.
Just chiming in to say that I remember seeing a .world mod telling us not to post full articles in the post or comments. The thing is, that mod had his account banned for COVID misinformation. Which, if I'm correct, is why you can't find any mention of the rule change?
A mod is not an Admin. I'm a mod of a community. That doesn't mean that what I say applies instance wide. My positions are categorically and exclusively my own, and not the position of lemmy.world's owners and administrators. This is why rules are usually written in third places, not in mod comments. If it's not on an official document, it's not official policy.