Yes, of course, but this is the beauty of federated systems running on open source platforms, isn't it? No matter the bias, both the tooling can be changed, and instances with a different bias can be set up. There is always going to be a bias, but there is no lock-in to a single one.

In this particular case, there are some possible technical solutions:

• The simplest one, would be to just allow instance admins pick which communities they wish to feature in their instance's "All" feed. Not an "all as controlled by users", but an "all as controlled by admins" (this in itself is a "curious" bias introduced by the upstream developers, given their political views... but let's not delve into that)
• A more advanced solution, but equally desirable, would be adding support for custom feeds (see: multireddits, Twitter timelines, Mastodon), with "All" being just one of them that happened to be controlled and promoted by the instance's admin, configurable through the same interface as any other.

It may not be possible, or even desirable, to remove all bias, but it can be left to the user to pick which one they like more.

(And don't worry, I'm also thinking out loud... since right now I'm unable to get hands-on to adding any of these options, and it's eating me alive 😅)