That's what we've been trying to tell the world about Iraq, Iran, North Korea, and even Cuba. That last one's strategically debatable, but for the rest "we should treat it as an attack" was a lie then.
Its no more or less of a lie now. Encouraging other countries to embrace reactionary foreign policy is no more of a good idea than following the US' lead on the matter.

You've got it backwards. Weapons-grade is more stable. Less stability is fine for reactors, because they are designed to manage the reaction on an on-going basis and not, in general, blow up.