I think everyone's afraid of getting sued.
No, but it does enumerate what is available which is the starting point for figuring out what is relevant to your use case.
If you want tutorials or guides relevant to your particular use case you can seek those out, but to understand them you will need familiarity with the set of available attributes and where they are or are not permitted.
Many (most?) tutorials online have flagrant violations of the specification. We need better ones that actually emphasize understanding WAI-ARIA and not cowboy markup recipe books.
> Please, stop doing this.
No, I will not stop telling people to familiarize themselves with the primary reference material. Reading technical documentation and specifications relevant to a project is not an optional step.
It is not complete in the ways you describe (actually testing real screen readers is crucial), but it is absolutely essential reading to begin with.
Well, I'm competent at HTML and CSS yet I never properly read the HTML or CSS specs either. Specs are generally a terrible place to learn a technology.
I simply don't understand how it's possible that the people who seem to care most about accessibility also seem to deeply, strongly believe that doing good accessibility ought to be very hard and time-consuming, and you don't deserve to call yourself a proper web dev without going through the rites. It's... not very accessible!
I would strongly recommend you do! Most web developers are unaware of a good deal of just what all is available to them in those specs (especially HTML).
As for "real screen readers", yeah. There needs to be a caniuse.com for assistive technology.
> You can refer to the WAI-ARIA standards.
Every time someone asks for concrete a11y advice for concrete situations, some joker refers them to WAI-ARIA. This is ridiculous! That document is extremely hard to parse, and it offers absolutely no guidance wrt which parts matter the most, or, say, how the various real screen readers used in the wild behave. Please stop doing this. Accessibility is hard to get right! Making people feel like they're idiots for trying is very unhelpful.