Is tax avoidance actually legal?

Not much in the way of economic theory here but a fascinating insight into the nature of the language associated with tax avoidance.

It's true that we assume that the super-rich are all engaged in something legal, tax avoidance. And yet, the accounting companies that help them to do this have paid millions of dollars in fines for facilitating under-reporting of the amounts that these people, and their companies, have paid in tax.

So why the linguistic reluctance to imply that some elements of tax avoidance are, in fact, tax evasion? I would argue that the media fear libel laws.