Obviously uncapped is not an end-all term here, MWeb and most other ISPs have more than one uncapped account, each made for different purposes/needs. Perhaps they should be more explicit, but they've said on these forums at least that the cheaper home accounts are not made for 24/7 downloading at full line speed (at least on 4Mb where bandwidth costs become prohibitive) which is why they've branded their other account as "Internet Addict" instead of just as an unshaped or business account.
If we accept that the far cheaper accounts should be treated as "home uncapped" or any other term which means they're not for overly intensive usage then there's not that much of a problem. It's not like they're being unreasonable at all, you could even download 400GB+ one month if you need to, but carrying on that type of usage at this price just doesn't make sense in SA unfortunately.