What makes the situation different today is that we only used to get non-credible threats from the DPRK. Suddenly (it only seems sudden, if we're being honest) the threats ARE credible. They're not, you know, catastrophic -- but the capabilities are there. They can kill a lot of people, well in excess of the "big deal" threshold (which is a rather arbitrary and personal line -- frankly killing ONE person is too much in my book). The threat has only grown larger ever since the DMZ went up, and now that the DPRK has its own nuclear deterrent, it's only going to grow faster. KJU needs to be brought to heel.
I don't mind if he stays in power (hell from an economic perspective, I much prefer it that way and you should too). But that nuke capability has got to fuckin' go. If it doesn't, you will see Japan re-militarize, you'll see posturing by the other regional players, and you'll see allegorical gasoline flung onto a whole slew of flashpoints (like Taiwan, the South China Sea, basically every scrap of ocean floor with mining rights attached). A weaponized-nuclear DPRK makes the world quantifiably more miserable, even if they never fire one for realzies. Hopefully our credible threats are registering -- I really don't want to have to topple the Kim dynasty, that would be really really super bad (for everyone NOT starving to death in the DPRK). BUT FOR THE RECORD, if they make us, we'll win very easily.