I've seen hundreds of comments over the years making the same claim as you. I've never seen an instance of this alleged toxicity. The attitude people display is not "Arch should be hard" but that Arch provides excellent resources to learn how to use the system yourself, and that the Arch way is for you to figure things out yourself. Expecting to be handheld will result in people reminding you of this, often quite directly. But in my view, what is more toxic than people saying 'RTFM' is people destroying a community with low-effort "help me now!" spam devoid of proper debugging details or any evidence they've read the documentation and tried to work it out themselves before asking for help.

Nobody says "Arch is a great first choice of distro" except with the explicit qualifier "if you want to get your hands dirty and read a lot of documentation". So nobody that comes to Arch has any excuse, in my opinion, for not bothering to learn how to do it. Again this isn't the attitude "Arch should be hard". It's the attitude that you shouldn't expect other Arch users to spoonfeed you when they've already provided a comprehensive wiki and installation guide and there are searchable forums full of troubleshooting you can refer to. Arch isn't made hard on purpose, but as a natural consequence of the way it is structured (minimally) it is difficult for a completely new user to get going unless they read the documentation.

Ironically, projects like archinstall prove that difficulty isn't a goal but an unfortunate side-effect: they're perfectly happy to make things easier if it doesn't compromise the integrity of the project. They're not going to automatically install a desktop environment for everyone just to make things easier.