Some of the other bigger instances out there federate with one or both just fine

I mean, the same is true for other PieFed instances. piefed.zip, for example, is federated with both (same admin team as lemmy.zip).

Like I said, this is inherently opinionated as any kind of defaults would be (themes, colors, user settings, etc.). I just don't agree that just because an instance is old and active means that it is a positive influence on or provides a positive experience for the average user. Just like I don't think forums like 4chan should be looked at positively just due to its age and activity. I know there are many that disagree with this, and there is nothing wrong with that.

Specifically, the piefed.social instance is a bit more opinionated than most other instances out there because rimu has pretty strong feelings about social media. Some of my contributions to the code have been to make PieFed less opinionated or to take some of those very strongly opinionated options/filters and make them configurable or optional at an admin level. So far, rimu has been pretty receptive to this kind of contribution.

At the end of the day, I am glad that all three threadiverse software platforms exist (people too often forget about mbin) and have been able to maintain a cordial working relationship. They each have different opinions, defaults, and features that might appeal to some users over others.