This is the kind of thing that should be easy
Maybe it could be easier, but I don’t think you should expect running something to be simple when it runs differently to almost every other piece of software on the system.
this proprietary piece of software the article is talking about sounds like an early 2000s game server to me where stuff like this was pretty common with linux support being an after-thought.
What I do think is pretty cool is that systemd’s declarative configuration is good enough to offer this kind of customizability (minus the documentation issue about “socket”): A setup like described here could of course be accomplished with traditional shell scripts, but everybody would need to write their own script or use their own distorts custom flavor of the feature, all incompatible with each other.
systemd offers this by default and all bugs found in this setup can be fixed once and and will work with every setup, even across distros.
As a sysadmin, this is a big advantage for me, all the negativity surrounding systemd aside.