80/20 rule.
When you are creating something like Lemmy, where you want wide uptake, you need to pander to the masses.
The /r/selfhosted surveys show around half of self-hosters mostly or exclusively use docker. A significant portion of the rest can use docker if needed.
If you're in the 20% that isn't covered by the most common setup, then it can be frustrating. But supporting that 20% takes as much effort as supporting the other 80% (see 80/20 rule), and when things are new it's just not where the effort should be focused.
So you have all those servers, but why can't you install debian or ubuntu server on one of them?
You could also get a $2/month VPS and run it on that. Beehaw is run on something similar (though apparently $12 a month, but a lot more users).