Gates are in countries that have treaties or on private property in places. They actually did have to ask thus the reason for the treaties and the fact that we saw gates were heavily guarded in the places that they were. And again now your using hypotheticals. The gates have no effect on humanity where as reeds device does have a direct affect on mutants. There is a big difference. A gate standing there doing nothing is no different than the many statues and monuments built all over the place that no one was asked before they were put up. Seeing a krakoan gate may be offensive to some but it doesn't actually do anything but let a mutant walk through it.