The short answer is; “yes” Facebook has been indefinitely banned in Uganda.
It has almost become a routine in Uganda to turn off social media whenever the country is approaching the polling dates. Like in 2016, social media was turned off for a number of days starting on the polling date followed by introducing the social media tax a few years later.
While Ugandans were hoping social media to be off for just a few days, in the presidential address on 12 January 2021; the president of Uganda Yoweri Kaguta Museveni declared an indefinite ban on Facebook on grounds that they were arrogant and partisan. He referenced the letter to the tech giants requesting to take action on some opposition pages that were giving information he claimed was mere propaganda but they never replied only later to suspend pages of NRM enthusiasts.
The president said that unless Facebook operates in a non-partisan way; it will not operate anymore in Uganda.