What goes for the rest of the world does not go for America.
"Many other governments, on the other hand, complain the United States and other big powers are moving too slowly toward scrapping their nuclear arms under the NPT."
It's quite clear who should have nuclear weapons, us, and who should not, everyone else. We're talking to you, Iran and North Korea!
This might be the exact reason why other nations are seeking them.
"The US feels compelled to preemptively attack a presumed nuclear-armed enemy, thus acting as the responsible keeper of world peace. And yet this type of rogue behavior may push some anti-US nations to seek nuclear weapons in defense, perhaps defeating this US strategy."
If we truly want to lead by example, an excellent first step might be destroying our own nuclear weapons. Until then...gulp.