The NPT is de-facto a universal treaty, any UN member who is not a member is in defiance even though de-jure they are not. Simply put, what I am saying is, Israel—along with North Korea, India, and Pakistan—are going against the expectation of the rest of the world when it comes to nuclear non-proliferation. They are in defiance with the nuclear norms of the international community.

Note that people also said the USA was in defiance to climate change treaties when they failed to ratify Kyoto, and when they withdrew from Paris.