Mr Khama, who was in office between 2008 and 2018, also took a swipe at Cameron’s long-serving President Paul Biya.
Mr Khama said President Biya was recently sworn in office at 92 years old “when he can hardly walk.”
He said the two cases were among many others which underscored a governance blight affecting Africa.
“It is totally unacceptable when an African leader, in order to stay in power, will resort to killing his or her own people. In order to stay in power, they will rig an election, as if they are God’s gift to their country. When you have a country with millions of people, for any leader to think they are the only ones who can be president is pathetic,” Mr Khama said.
The retired president also called out what he termed as a tendency by some African leaders to intimidate opposition figures through arrests and banning opposition parties.
Mr Khama was the chief guest at the ceremony which was meant to mark two years since Lukenya University established the Pan-Africanism Institute to promote African renaissance.
Meanwhile, a shadow of former Prime Minister Raila Odinga hovered over the ceremony. Through skits and songs, students hailed Odinga as a champion of democracy.
Speaker after speaker took turns to pay glowing tributes to the former ODM leader, while calling on the youth in Africa to raise up and challenge bad governance.
While pledging his commitment to the ideals of Pan-Africanism, Wiper Party leader Kalonzo Musyoka challenged young people to challenge bad leadership.
“The surge of youth led Pan-Africanism is not accidental. Nineteen coups in just four years, coupled with the persistence of one-term presidencies are warnings we cannot just ignore,” Mr Musyoka said.
Makueni Governor Mutula Kilonzo Junior called on African leaders to challenge the misrule in Tanzania in the spirit of the former ODM leader.
“We shall be failing Mr Odinga by not doing so,” the Governor said.
“Do not wait for permission to lead. It is your right. As the youth, you are the generation that will take Pan-Africanism beyond rhetoric and make it a lived reality. In your hands lies the power to dismantle poverty, corruption and inequality,” he said.
Lawyer and scholar Prof PLO Lumumba called on the youth to emulate the great pioneers of Pan-Africanism such as former Tanzania President Julius Nyerere.
