Why do the warhawks focus on Iran?

In their fervor to prevent them from getting a nuclear weapon.
There is little to no evidence that Iran is even pursuing a nuclear weapon, and historically, the country is not prone to starting wars.

Meanwhile, North Korea openly develops nuclear weapons, its leadership is far more crazy than that of Iran, constantly flaunts their “might” with their missile tests, and is a direct threat to South Korea and Japan.
And yet, the warhawks are in no rush to push for a military solution to “liberate” NK.
Why do you think that is?