Except for the fact that they have been for decades.
I don't really think that's the case. Seems like there are countless examples of costumed vigilantes violating that trust. And the speed with which the populace embraced Superhero Registration following the tragedy at Stamford indicates that the public had long felt that superheroes had not lived up to their end of the bargain.
And moreover - what choice were the people ever given? Costumed vigilantism was basically rammed down their throats. Few street-level superheroes ever asked anybody if they could engage on a frequently-violent campaign to "clean up the streets." Few members of the public were ever given the opportunity to weigh the supposed advantages of costumed vigilantism against the likelihood of escalation of conflict by the forces of criminality.
But in the world of comics, it's been a net positive by any measure you'd care to name.
Is it? The first comic superhero
The Clock was largely little more than a masked detective who solved petty crimes and fought thugs and organized crime types. By the time we get to House of M, even
the heroes themselves are radically reshaping reality in ways highly detrimental to the nonpowered populace. That's after about 8 decades of slow escalation in terms of the danger of the villains, their organization, and the destructive power they're able to wreak.
I think there's a pretty substantial case to be made that denizens of the World of Comics are substantially worse off as a result of 8 decades of costumed "heroics."
By regulating superpowers, you are restricting the very abilities that make superheros who they are.
Don't you think that, for someone who has Olympic-caliber talent at target shooting, the operation of firearms is a part of who
they are? Don't you think someone like an attorney or a policeman, who dedicates themselves to the ideals of justice (to the extent that those figures do), what they do is part of what makes them who they are?
A heavyweight boxer may define
who he is by the fact that he's good at punching people, but that doesn't mean we let him punch anyone he likes.
You know I have an anti-authoritarian streak as wide as the day is long. I don't relish the thought of government intrusion and control over the lives of private citizens. But superheroes
themselves are another kind of authority, an elite, unelected fraternity unaccountable to those most affected by their decisions. There must be some middle ground between the unchecked exercise of their power and the dystopian police society the Superhero Registration Act ultimately devolves into.
It would be like requiring a boxer or an MMA fighter to register themselves before they be allowed to go in public.
But we do have registration and regulation of both boxing and Mixed Martial Arts competitions and competitors.