Do you think this would have been averted if they took all the measures you are proposing ? There are no set guide lines here according to which the government is taking down stuff.. This is not DMCA related to create an process to take down stuff.. Even if they could not find the contact page, taking the whole website seems to be ridiculous thing to do.
I think things like this will make websites with user generated content to move away from .com domains and even move into countries where there is more due process to things like this.
I think there's a decade of history that shows it could probably have been avoided - they're not the first free-x-hosting company to ever be abused for phishing.
The same risk existed last year alongside the many exploitable-by-phishing flavors of hosting. Although this wasn't even a domain seizure, this is just an overzealous domain registar which has also, always, been a risk to web services.
I think things like this will make websites with user generated content to move away from .com domains and even move into countries where there is more due process to things like this.