Most internet users don't have the savvy to use the deep web. I'd put myself far above average and even I am in the dark as to its machinations.
The problem with the UN controlling DNS is that they will be able to subtly control what gets published out in the mainstream internet where the vast majority of people swim. Effectively removing voices against globalism and governmental control from the public discourse.
Most people won't be able to find www.breitbart.com if the DNS record is purged to deny access, most people won't be able to figure out that 72.21.91.19 is their IP address (and for some reason entering their IP address still doesn't take me there).
Sure, many of us will figure out ways to get to our underground lairs, but we'll still be walled off in little ghettos of feedback loops and confirmation bias and not actually influencing opinion or making any changes.
This will sway elections, this will impact public opinion and this will change the nature of governments around the world for the worse.
Once the UN or some other international group of globalist schmucks gets control of DNS I suspect that gun manufacturers and gun related sites will be among the first IP addresses blacklisted.
Time will tell.
