The poster said "I find that...", which is equivalent to "In my experience...". How is someone posting their experience the same as making a "sweeping over-generalization"? They never flat-out said "ALL textbooks".
Also, surely if it were not accurate you could easily drop the name of a good textbook without any trouble, since you apparently have enough experience with them to make the distinction.
Also, surely if it were not accurate you could easily drop the name of a good textbook without any trouble, since you apparently have enough experience with them to make the distinction.