Excellent question!!

• It is a common problem and probably the main pain point in trying to interact with lemmy communities from mastodon. You’re not alone here! The quickest advice if you want to engage with lemmy communities is to just create a lemmy account and use lemmy UIs/Apps.
• Nonetheless, it would be nice if it weren’t a problem, as you ask! Unfortunately, as I understand things, the problem is entirely on the mastodon end of things, and mastodon is well known for both being somewhat brutalist, simple and stubborn in its ideas about what their platform should be, and, slow to change and develop new features (word is at the moment that development on any new features has actually come to a standstill).
• So I wouldn’t get my hopes up for this problem to disappear any time soon, and generally, my sentiment is that the fediverse would be best served by spending energy on moving on from mastodon as the super dominant platform. Right now, mastodon comprises ~88% of monthly active users of the whole fediverse. Personally, I’d like to see that get below 50% and ideally around 20%, assuming mastodon doesn’t change too much.
• The reasons, AFAIU, why mastodon doesn’t provide a good interface to lemmy:
  • Mastodon flattens all feeds into a single reverse-chronological feed. There’s no threading of replies (which is seriously fucked for major though niche social media platform in 2023) or any sort of filtering or sorting.
  • Mastodon, in line with above, has no concept of tiered content. There aren’t posts with comments attached. Everything is a post that can also be a reply to another post. As a result, everything just gets dumped into the feed like a giant stream of stuff. There’s no way, that I know of, to view only top-level posts (that is, posts that aren’t replies). Along with the lack of threading, mastodon is basically antithetical to any structuring of online social media content, which is striking given that we have basic structuring in every other form of online content from email to old school message boards and forums to facebook and twitter and youtube and any normal webpage.
  • Mastodon has no concept of groups, where a lemmy community is a group. These manifest on mastodon as users/bots that boost. But that’s not what a group is really (or at least how lemmy/kbin and probably facebook/friendica see them). They’re spaces in which multiple people (ie a “group”) can post in regards to a specific topic or parent post. So already, apart from the above points, you’re fighting uphill when it comes to mastodon and an alternative more structured format of social media.
  • Mastodon is extremely limited when it comes to the formatting of posts. It’s basically all plain text with some link formatting and nothing else. No markdown support. And, most importantly, little respect for the formatting of other platforms, where, for example, a lemmy post basically doesn’t make sense when viewed on mastodon: no links are provided (when they’re part of the lemmy post), same goes for images AFAIU, and, only the title is provided while the body is cut out and you’re left with a link to the original page of lemmy post. Basically, it’s useless and disrespectful to the platform. As I understand, lemmy is essentially complying with activitypub (?) in the way the information is packaged, it’s mastodon that isn’t doing the work. And why would they when their view of social media is so brutalist.
  • Mastodon has no facility for backfilling, which is fetching all of the relevant content when prompted by a user. Instead mastodon relies on everything being on the local instance, which is filled up by all the users followed by users of the the local instance. If that doesn’t provide some content, then you never see it. Communities/groups work differently. The idea is that you’re supposed to see exactly the same replies/comments no matter which instance you’re on. So on mastodon, the idea of receiving only top-level posts in your feed, and then, when you’re interested, viewing all of the comments, without those comments always filling your feed, doesn’t make sense. As that would be backfilling and it’s not something mastodon does.

All up, I can’t see any of these problems, let alone all of them get better any time soon. And, IMO, this is to the detriment of mastodon and, as it’s the dominant platform, the fediverse at large. Communities/groups are a fantastic way to connect with people. Apparently mastodon will be implementing groups of some sort, which might help. But then there’d still be the issues of whether mastodon interoperates well with other platforms. Given all of the above, I wouldn’t have high hopes, though I’m happy to be proven wrong.

More broadly, I think a successful fusion of microblogs, normal blogs and communities into a single interface/platform is one of the next steps the fediverse can make in its growth as a major alternative to big-social-media. It’d be novel, a killer feature arguably and it’d bring people together more effectively while also giving people plenty of options for how and where they want to connect.

I think the time is ripe for mastodon alternatives, like lemmy and kbin, to get more attention and investment from the fediverse at large.

end rant (sorry!)

that is not how it is on lemmy itself

Yes it is, it just doesn’t look like that in the lemmy front end.

Boosting posts that tag the community is how the community shares content with subscribers to the community

Eventually Mastodon will get a standard implementation of quote-toots. At that point I’d think the appropriate way to represent Lemmy comments as toots would be to represent the toots as quote-tooting the root (post) toot. You’d still have to click the toot to see the context of the parent toot, but that’s a client problem - imho clients should always have an easier way to view the parent of a reply-toot than doing a full-page nav to the reply-toot in context of its thread, and the fact that they don’t is a problem on every twitter-style microblogging platform. But you’d have quick context of which article they’re replying to.