Man, that is such an indoctrinated thing to say.
Taxing wall street speculation is a huge mistake. The whole idea is not even in the right ballpark. What does that even mean? It's just a bunch of buzzwords strung together to appeal to people's emotions. Market speculation is a
good thing. It's been vilified over the past decade because the government was letting cronies borrow free money with which to "speculate". They reduced it to what amounted to gambling. That's called moral hazard in economic terms. So who is to blame for a gambler losing? You can't blame the blackjack dealer or the gambler. The guy who let the gambler bet an unlimited amount of other people's money is who should be blamed. Speculation would become even more beneficial if the real problem were addressed by having free and unlimited access to other people's money. In other words, let the market set interest rates.