It's largely a matter of where the community gathers, that ends up giving this impression. You mention r/rust downthread - r/Julia is quite inactive in compari

It's largely a matter of where the community gathers, that ends up giving this impression. You mention r/rust downthread - r/Julia is quite inactive in comparison. However, the places where Julia discussion actually happens - Discourse, Zulip, etc. - do contain a lot of criticisms, wishlists from other languages, roadmaps for improvements, etc. But these are not places you would randomly come across if you're not involved with Julia, like a subreddit would be. And the scientific/academic focus of the language that you mention is actually another reason this happens. When the language's users are (primarily) developers, they (we) nitpick and think about alternate designs and blog about them for no reason at all. The average Julia user instead would just ask in the discourse/other forums, maybe complain, and then move on with their research/engineering problem. So the blog articles that end up getting posted here are most often by the core language/package developers announcing new features, breakthroughs, and other positive news.