He's not having a go at scientists, he's making the distinction between abstract theoretical mathematicians who call themselves scientists and the empirical physics of the scientific revolutions of 15th and 19th centuries.
Why spend on these types?
because
he created
this
Faradays law
is our economy
The rigor involved in developing a modern electrical engineer should not be underestimated. Certainly not a waste. The keys you are privileged to tap and all the equipment in your thumbnail come from these talented men and women.