You've got to remember, some training courses direct much of their tuition towards their own products. Many years ago just about all supplier led courses did this. Today the better courses do not do this, however they all have to teach by 'The Book'.
You use this information as you gain experience 'out in the field' and discover what works best for you, what to avoid and how far you can push things with a real 'minger' whether it is sythetic or 100% wool. Same things go for suites too, although a little extra care and caution is required. Before you know it, you will recognise what you are about to clean, and how to do it with confidence.
However don't expect other cleaners to always agree with each other, even those in the business for many years will have different ways of doing things.
Dave.