People don’t just RTFM for the same reason people learning a language don’t just read a dictionary.
The manual doesn’t tell you how people do things in practice, common gotchas you need to handle, tooling, or how to combine different bits together. Not to mention there are multiple manuals, and it’s unclear to a beginner with which one you’d start.
anything i need more examples of, I head to MDN and css-tricks.