I thinking reading fast is a sign of immaturity. When I was a teen I swallowed books whole. I absorbed sentences in a glance. But as I've got older I've slowed down. I re-read more. I choose more carefully. I get deeper into things. Fast reading is for skimming over the surface of things. Which is fine but definitely not a sign of maturity.
I agree generally, but it depends what you're reading. There are many books that "could have been an article" -- these might not be worth reading slowly.
