Islam has not been banned in Angola. From Al Jazeera:
Angola's government has denied it had banned Islam and closed mosques in the country, after media speculation that sparked outrage among Muslims worldwide.
"There is no war in Angola against Islam or any other religion," said Manuel Fernando, director of the National Institute for Religious Affairs, part of the ministry of culture, on Tuesday.
"There is no official position that targets the destruction or closure of places of worship, whichever they are." Fernando told AFP news agency.
While mosques have been closed/destroyed in Angola, this was apparently done due to their lack of permits.
But according to the ministry of culture, those closures were related to a lack of necessary land titles, building licenses or other official documents.
A witness in the province of Uige (Carmona) told Al Jazeera that the closed mosques were hastility built by expatriate communities from west and north Africa who needed a place to perform Friday prayers.
“It’s true that several mosques have been destroyed and others simply shut down in the last few months. Most of the mosques that were destroyed were built without government permission. Two authorised mosques in Luanda are still operating without a problem. I have not heard of any official decision to ban Islam or prohibit Muslim prayers in mosques.” Ahmed ould Taher told Al Jazeera.
But it does appear that Angola does not officially recognise Islam as the number of Muslims in Angola is apparently below the required 100,000 mark. This figure might be inaccurate:
The oil-rich southern African nation has a population of about 18 million people, several hundred thousand of whom are Muslims.
Religious organisations are required to apply for accreditation in Angola, which currently recognises 83, all of them Christian.
In October the justice ministry rejected the applications of 194 organisations, including one from an umbrella Islamic community group.
OnIslam.net, the site that appears to be largely responsible for publicising this rumour, also offers a backhanded clarification:
In light of the mentioned political and economic environment, the contended discussion of banning Islam in Angola can be discussed.
The short answer to this question is that Islam did not get “banned” in Angola, simply because it was not officially approved in the first place. Until this day, Angolan Muslims are not able to get government approval for their religion to be able to build mosques, secure their standing as an officially registered religious group, and gain legal religious rights, among others.