Well if you want me to extrapolate this to rA...
When I was making this post I was going to point out how even in the wiki it either promotes the use of poor practices or does not mention any basic ones.
The wiki is a part of the rathena website it is, by all intents and purposes, the official rA information hub. The wiki guide writers have included detailed instructions for downloading, installing and configuring the rA software (and its dependencies as well as some 3rd party software), so there is a reasonable obligation to at least include basic server security instructions or, failing that, mentioning them and providing external links.
I would imagine people would default to the defense of: "it's the server owner's responsibility" and that reasoning is wrong. If we're going that route, then why include any support for server owners if it's all supposed to be "their responsibility"? With that reasoning, they should be knowledgeable enough to be able to download, install and configure the software (and dependencies and unnecessary 3rd party software) without any guides. Sounds like elitism, doesn't it?
So why are there guides available on the official wiki? Because there are people that realize many server owners don't know what to do and need a walkthrough to get them started. Again, there is a reasonable obligation to at least help them with things like setting up their firewall and discouraging the use of software that is full of holes all the time.
TL;DR throwing responsibility to server owners (yet providing step by step guides to everything (except the stuff that really matters)) is a tired elitist excuse from all the way back to the eA days.