To be fair, I'm sure they actually did fail to consider it. I mean who would in their right mind, but still, it probably was not considered.

Uganda has been infiltrated through missionaries by Christian Zionism for a long time, and they have historic ties to Zionism:

From the pulpit to the Hague: Uganda’s Christian Zionist dilemma

The beginnings of Christian Zionist thought in East Africa came via the colonizer, used explicitly to dominate Negro peoples. Later, East African elites absorbed and politically instrumentalized these ideas, even to the point of justifying genocide and sympathizing with it.

When Zionism Invaded Africa: The Story of General Idi Amin and Israel’s Influence in Uganda

By January 1971, Idi Amin and his army overthrew President Obote with help from the Israelis and the CIA [...]. In 1976, The New York Times interviewed a retired Israeli colonel who helped Idi Amin topple Obote in 1971 [...] Bar-Lev supported General Amin because Obote was ready to expel the Israelis

The pernicious influence of Christian Zionism in Uganda was evident last year when a Ugandan ICJ judge said:

“The Lord is counting on me to stand on the side of Israel.”

“I have a very strong conviction that we are in the End Times. The signs are being shown in the Middle East. I want to be on the right side of history,” she reportedly said. “I am convinced that time is running out. [...] I am humbled that God has allowed me to be part of the last days.”