The data is called "history".
The US started with no financial regulation; we got regulations and regulatory agencies over time, mostly in response to problems. The exchanges whose history I'm familiar with started small and became more internally regulated over time, again in response to actual problems. Those exchanges were generally run by traders, who are dispositionally anti-regulation. But they are also strongly motivated to have smooth-running marketplaces that are generally trusted. So they made some tradeoffs and found ones they were pretty happy with.
The fact that no devil-may-care marketplace has survived, and the fact that countries with successful financial marketplaces have all converged on similar approaches is as reasonable set of evidence that regulation has value to market participants. You will never really have a control group, because the "no regulation" control group fails hard enough that it isn't sustainable.
> A policy being wildly popular doesn't mean it's socially constructive or ethical.
It doesn't prove it, but for regulations that are popular with all sorts of market participants, it's excellent evidence. The alternative explanation, that you alone are way smarter than all the people who are experienced professionals on many sides of the marketplace, is not particularly persuasive.
> It is not a fetish to not want to be subservient to a centralized gatekeeper and be forced to get permission from it to interact with other adults.
Sure. A desire only becomes a fetish when the desire becomes hugely dominant, pushing all rational consideration aside. Which I believe is often the case in the cryptocurrency/ICO space. For whatever reason, cryptocurrency advocates often value the "you're not my DAD" kind of freedom way more than they value success.
As an example, look at Bitcoin. 8 years in, and its real-world, non-criminal use is approximately zero. That's despite all the hype about Bitcoin international money transfers, Bitcoin shopping, Bitcoin ATMs, et cetera, ad nauseam. In roughly the same time M-PESA has ended up with 30 million users and 6 billion transactions per year. And those are actually useful transactions, not financial speculation.
I have no beef with cryptocurrency advocates pursuing their personal desire for radical independence. Godspeed, and may their Heinlein novels find a nice spot in their seasteading cabin. But I do object to the enormous ahistorical hype and denial that has gone along with it.
It's fine to say, "Well, sure, regulation would make things better for many practical use cases, but we think a high endemic level of fraud and low real-world impact is an ok price to pay for the very narrow kind of freedom we're dedicated to." But I don't appreciate the quasi-religious evangelicalism about the magic power of technology and markets to make everything sunshine and rainbows; and the concomitant notion that the rest of society should just follow their vision and values, never mind the human cost.