I’d suggest that the short version is “don’t worry about it”.

The slightly longer version is that the Lemmy equivalent of a subreddit will have a kind of home-base instance (eg. based on lemmy.world or aussie.zone or whatever else). For the most part, it makes no difference. But some lemmy instances might choose to block certain content. (For example, they might block all porn content or something); and so depending on where you signed up, you may see a slightly different selection of posts on your feed.

You’re on aussie.zone. You can see a list of what is linked & blocked for you here.