I just can't see this many people having cross transmission on sexual contact alone given the stats being quoted here it does not compute!!
Number of HIV-infected individuals in Angola: 240,000
Number of HIV-infect individuals in Botswana: 350,000
Number of HIV-infected individuals in Lesotho: 320,000
Number of HIV-infected individuals in Malawi: 900,000
Number of HIV-infected individuals in Mozambique: 1.3 million
Number of HIV-infected individuals in Namibia: 210,000
Number of HIV-infected individuals in South Africa: 5.3 million
Number of HIV-infected individuals in Swaziland: 220,000
Number of HIV-infected individuals in Zambia: 920,000
Number of HIV-infected individuals in Zimbabwe: 1.8 million
ANSWER: AIDS vs Malaria | Radical Reference
Besides the original explanation of HIV infection leaves for a lot more questions than answers...
These are numbers that coincide with mass infection on a massive scale that is more than just sexual contact.