American embassy cables describe a 2009 UN-sponsored meeting which gay rights campaigner David Kato spoke at, the Guardian reports.
Mr Kato, who was murdered this month, was openly mocked as he nervously read a speech against a bill to strengthen Uganda’s laws against homosexuality.
The US diplomat wrote that the homophobia of bill sponsor David Bahati MP was “is blinding and incurable”.
The cables also refer to anti-gay pastor Martin Ssempa and Ugandan ethics minister James Nsaba Buturo.
One said: “Bahati, Buturo, and particularly Ssempa’s ability to channel popular anger over Uganda’s socio-political failings into violent hatred of a previously unpopular but tolerated minority is chilling.”
The memos also showed diplomatic attempts to combat the controversial bill.
The status of the bill is currently unclear but anti-gay feeling runs high in the country.
Gay rights campaigners in Uganda are calling for a full investigation into Mr Kato’s death.
One man has been arrested and police say Mr Kato’s activist was not relevant.
The activist had received death threats after successfully suing a newspaper for publishing his name, address and photo in an anti-gay campaign.