Sforno on Exodus 18:9/ספורנו על שמות י״ח:ט׳

1ויחד יתרו, he did not rejoice over the destruction of Egypt as a major power. This is what he should have done if he had been truly concerned with the honour and glory due to his Creator. We know this from Psalms 58,11. However, he did rejoice over the well being of the Israelites. He behaved like someone whose heart is moved by the tears of the oppressed.