Cameron's dad's involvement in offshore finance is no secret.
exactly and neither is it illegal. People can question the morality of pumping your money offshore to reduce your tax liabilities through legal means, but that doesn't suddenly make it headline worthy.
If you had a referendum at any point, asking whether it's acceptable for people to use offshore tax havens to avoid paying tax, the result would be a resounding no.
It might not be illegal, or a closely kept secret, but the "people" are never offered the chance to stop it. It's never on the ballot paper. Why?
Clearly these schemes are not in the national interest, and many of them exists in jurisdictions under the direct control of the UK government.
The politician keep quite about it, and whilst it's not in the forefront of peoples daily lives, it gets conveniently "forgotten" about.
These leaks are newsworthy, because it raises the profile of something which shouldn't exists, and would not exist if it weren't for the rich having effectively bought government off around the world.
The only difference between tax avoidance on this scale, and tax evasion, is tax evasion is the result of governments doing their job properly. There is no point in evading tax any more.