Several folks hold the opinion (here's a recent one) that the Lemmy devs, acting as primary moderators for the lemmy.ml and lemmygrad.ml instances, have ignored moderation of pro-CCP, pro-communist discussion threads on those instances. This ends up being detrimental for Lemmy's reputation overall, as:

1. Those instances have some of the highest membership numbers, and as word-of-mouth spreads will mean a lot of newcomers to Lemmy will land into those large instances
2. If the devs don't moderate their instances a certain way, what are their motives that might bleed into the development direction that Lemmy itself will take? e.g. The devs' opinion on how to implement a slur filter

My own personal opinion here is that as long as the devs aren't building anything malicious or overly political into Lemmy, I don't really care what their personal beliefs are. I work with devs all the time that have different ideological or political beliefs, that doesn't change the quality of the code. Open-source software can be forked and modified if the Lemmy devs cross the line, and by design each instance can run their own version of the underlying software. How the Lemmy devs moderate their instances is only a reflection of their ability to act as effective moderators, which is why (again, by design) choosing your "home" instance is the most important aspect of engaging on Lemmy and the wider Fediverse.

I can only speculate with zero evidence, but it's possible that the creator has strong feelings about communism, neo-nazis, or reddit, and others involved have other stances.

I don't think the app or Lemmy itself was archived due to technical reasons though, it seemed to work decently enough.

I don't know the details but from what I heard the developer was bothered that Lemmy was either "too communist" or "not communist enough". I can't remember which one it was and no guarantee that it's really true (it's just hearsay and I might be mistaken).