Why don't evil people understand Mishpat?
Rashi: They do not put to heart the future punishment, to contemplate it and return from their evil way and be saved. Tanchuma applies this to Dor ha'Mabul.
Malbim #1: Those who abandon Torah praise a Rasha (4) because they do not understand Hashem's Mishpat, that He will return to a Rasha like his evil.
Malbim #2: Evil people praise a Rasha who steals Mishpat and conducts with murder, for constantly do evil, the opposite of Mishpat, and do not understand the dearness of Mishpat.
Those who seek Hashem, do they understand everything?
Rashi: They understand good and evil.
Malbim #1: Shomerei Torah seek Hashem. They understand that all Hashem's ways are with Tzedek and Mishpat. Therefore, they contest [those who praise a Rasha - 4].
Malbim #2: They understand and teach to all the ways of Mishpat, and the evil of the Rasha's conduct.