Everyone has to start somewhere.
If you take a university student who has just left home and never cooked for themselves and tell them "just pour a glug proportional to the ingredients"...that's pretty close to useless for them, especially since they don't yet an intuition for what things you can freehand (and how much you can freehand them) and which things you shouldn't.
After all, you (probably) wouldn't ever say "I just open the Morton's salt and pour a glug in" because getting salt wrong even by relatively small amounts has a big impact on the final dish.
That said, I agree with you that recipe writers usually do a poor job of laying which things fall more on the "suggested amount, you can just eye ball it" end of the spectrum and which ones are "you should really pull out at least a spoon to get close on this one".