Because it is specifically tailored for hobbyist users who would want to build their OS bottom up, stack-by-stack. In Arch world, they claim they strive for simplicity and that simplicity is achieved through forcing you to familiarize with every part of your system so that it is simple and easy for you to pin-point the root when an issue occurs. They put a lot of effort in writing a great documentation that the Arch wiki. Usually the BBS community don't expect you to know everything but want to see that you did your own part before seeking community help. Please don't read it as an excuse for the cockiness of some community members but plenty of times the users are at the fault. Answer to many questions on BBS are simply direct citations from the wiki. There is nothing wrong if someone is not willing to read that much just to get an OS working, but then they should just acknowledge that they don't fall into the targeted user-base and stick to something else that suits their need better.