How are OT Wars Just?

The word translated as "LORD" here is YHWH and refers to the superiority of God. This is His proper name, and it serves as the most personal and holy representation of Him in language.The verse makes a rather obvious statement by saying something to the effect of: "The most supreme and all powerful God is, in fact, king." This certainly done for emphasis. Psalm 10 is a cry to God expressing discontent with the schemes of the wicked, but verse 16 marks the turning point that most, if not all, of the Psalms have. Here we are reminded that our God is YHWH, which should have an impact. We are also reminded, specifically, that He is king. He is sovereign and glorious and his decrees are firm. This is not temporary, but rather we are reminded that His kingship is eternal. It will last, not forever, but forever and ever for it reaches beyond our furthest grasp in both time and magnitude.

We as mankind have insulted this power. We have disobeyed his decrees, we have mocked his majesty, and we have dare to define his sovereignty. Any king of man would not tolerate such an insolence, as it not only offends themselves, but it also threatens the order of the society for which they are responsible. Thus, it is the height of justice for the Creator and King to banish lawless rebels from His own creation. This is why "the nations perish from His land". If God claims it, He's taking it back, and He is just in doing so. Anything outside of complete removal is mercy.