The problem these and other less democratic countries have is that the government can stay in power using resource extraction wealth to pay their police and armies and they do not rely on direct taxation for their revenues. The reason the people do not have a say in how money gets spent is because there is no political reason to ask them. See De Mesquita and Smith on that dynamic.

The problem for developing countries is not foreign bank "secrecy," (a presumptuous term itself) it's their domestic resource curse and other governments propping these leaders up. For these third party countries to decline to sign surveillance agreements and tax treaties that disadvantage them is not "secrecy," its sovereignty.

Attacking the sovereignty of financial centres is a sordid attempt to bar the exits and prevent capital flight when large state governments impose ever more wealth destroying policies to buy votes.

If by "fringe," you mean that solving the spending problem before the revenue problem is beneath discourse - the policy makers of every Tory, Republican, and Conservative party in the western world would probably like to have a word. As would a number of Liberal parties as well. Contributing to lazy propaganda that advocates for soaking "the rich," seems rather more a fringe activity, and further, if it does not include an understanding of the mechanisms of finance, one that is intellectually dishonest at that.