Sforno on Exodus 22:27/ספורנו על שמות כ״ב:כ״ז

1אלוהים לא תקלל, even though you may feel that the judge has judged you unfairly, you must not curse him. The reason is that no individual can judge his own guilt or innocence objectively.

2ונשיא בעמך לא תאור, cursing the legitimate authority of a country, its official rulers, will frequently result in the whole population experiencing the negative fallout of such curses. Compare what Solomon has to say on this in Proverbs 24,21 “fear the Lord my son, and the king; do not associate with those who keep changing.” [the author appears to read into above verse that hereditary royalty is to be obeyed in preference to elected rulers who are elected only for a limited period of time, and can be replaced by the will of the people even during their term of office. Ed.]