Everyone is in favor of free speech. Hardly a day passes without its being extolled, but some people's idea of it is that they are free to say what they like, but if anyone else says anything back, that is an outrage.
It seems superfluous to constrain trading in some of the newer derivatives and other innovative financial contracts of the past decade. The worst have failed; investors no longer fund them and are not likely to in the future.
The self-styled practical man of affairs who pooh-poohs philosophy as a lot of windy notions is himself a pragmatist or a positivist, and a bad one at that, since he has given no thought to his position.