How to we explain Hashem getting angry with the middah of "Kel," which is compassion?

• Chochmas Manoach - Parable to a merchant exacting payment from a friend an enemy. When Hashem punishes Klal Yisroel, he administers it slowly and over time. Alshich - d'var yom b'yomo. Chidah explains the Mishna in Avos accordingly. Ya'avetz on Rosh Hashanah that this is the difference between the judgment of Klal Yisroel and the other nations.
• Tzlach - Although He gets angry, it is only for a moment.
• Rav Dessler - Tranquility leads to sin; knowing that Hashem has anger keeps a person on his toes.

Maharsha in Menachos 110a that the midah of "Kel" is not the same as the "Shem of Four Letters." Rabbeinu B'Chaye in Bahaloscha that the midah of "Kel" is "din that includes rachamim.