Hi. In my opinion(as I can not speak for afrihost).
P2P downloads sound to me like it's a big source of income for an isp.
The way I see it almost everybody with an internet connection downloads a torrent at some stage, and if this was blocked people would not have the need to have higher linespeeds, which in turn means less income to the isp.
If you think about it, a 2mb line is more than adequate for browsing and normal downloads for a home connection.
So in conclusion, if an isp was to block P2P downloads, I can see people downgrading their lines as there is no reason to have the speed, but nowhere to use it.