In your insights you mention a contradition from the Midrash which states:
"Hash-m said, 'Although they were My enemies, I wrote in My Scriptures (Mishlei 24:17), 'Do not rejoice at the downfall of your enemy'" (Yalkut Shimoni, Mishlei, end of 2:960; Pesikta d'Rav Kahana, end of #29). According to this Midrash, even we -- who were saved from the hands of the Egyptians -- should refrain from showing joy at the downfall of the Egyptians!
I don't see the contradiction. It's perfectly consistent with what you wrote above it. This Midrash is saying Hash-m does not rejoice (hence, the capital "M" -- My enemies) over the downfall of the wicked. However, we, who were saved from the Egyptians, can. I don't get why you think this Midrash, at least as quoted here, contradicts the earlier explanation you gave. This Midrash only teaches that Hash-m doesn't rejoice; we, however, do.
Yaakov Astor, Monsey, NY
It might not have been clear from the Insights, but the full quote from the Midrash begins before the section that you cite above. Here is a copy of the section of the Insights that is quoting the Midrash:
"The Midrash says that we recite the full Hallel only on the first day of Pesach and not on all seven days of the festival, because the Egyptians were drowned in the sea on the seventh day of Pesach. Hash-m said, "Although they were My enemies, I wrote in My Scriptures (Mishlei 24:17), 'Do not rejoice at the downfall of your enemy'" (Yalkut Shimoni, Mishlei, end of 2:960; Pesikta d'Rav Kahana, end of #29)."
As you see, the Midrash tells us not to recite Hallel. This implies that even we should not rejoice at our enemy's downfall. This contradicts the Gemara that teaches that we may rejoice at the enemy's downfall (even though Hash-m does not rejoice).
Best wishes,
Mordecai Kornfeld