The first objection would be that you are not giving your pention to the ANC, you are giving it to the Government to use for 'investments'. (Although we all knows that there isn't any noticeable between the two as the Ruling party ANC determins the way the Government implements laws and regulations. And also the people implementing those laws and regulation, even though they work in government, follows ANC principles.
That said. in both cases if I had a choice it would not give my money to any of those two entities, or even ANY political party of government to 'grow'. They are just not geared for that.
It can be argued that governments job is to create the environment for the economy to function (thus ensuring roads are built and maintanced and power is supplied) at a cost efffective and non-wasteful way ofcourse, but if not possible that there might be some cross subsidizing required.
Think about roads. There is no way the tarred road outside my house will directly contribute to the economy, but it enables me and my neighbors to get to work effectively and somewhat efficiently. But the expense of the road itself and maintenance is likely not going to be directly covered by my municipal rates and taxes
So government will spend the money on capital projects, whether it makes a profit or most likely not.
Whereas private institutions will invest the money there where it might provide the best returns for the client.
Different mindsets.