It's interesting that a lot of people think that the solution for some problem is to ban it. If only it were that easy. It's the equivalent of liberals deciding that mandating a higher minimum wage will solve the problem of poverty. No, it won't. Banning something to take care of it would be a wonderful tool if it worked (and more importantly it weren't abused as a power. then again you could just ban abusing the power to ban stuff). In the poverty example, banning poverty won't eradicate it. That's not to say that the rationale behind banning something isn't being driven by improper motives.
The potential unintended consequences? Angola may have made itself a target for terrorist actions.
Another banning in the news this week - Microsoft partially banning swearing on XBox Live.
Great intentions - protect the children, help sales. But will swearing stop? Not at all.
It's impossible to ban ideas. You can ban books but not the ideas they contain. You can't ban communism or capitalism. You can't ban belief in God. You can't ban personal preferences. Even though Putin tried in Russia.
There's a difference between banning stuff because you don't like it and simply choosing not to support it or enable it (or even boycotting it). Doing the latter things is acceptable and is the at very crux of personal liberty - someone else can do what they like and you can do what you like to not support it.
The legal foundation of courts are not established to ban illegal behaviors but rather to through the use of punishment dissuade people from illegal and immoral activities such as murder. If banning murder worked, the court system would not be needed.