But in the context of the discussion, avoiding taxes is being used in a negative way by implying that the companies are not paying taxes that they should be paying by whatever criteria society dreams up, such as "fair share". I simply object to this characterization since these companies are following the law until a tax court says otherwise.
But that's an important point.
Traditionally "Tax evasion" was legal, and "tax avoidance" was normal, acceptable, and purely legal.
The weird accounting practices of some of these big firms are pushing a language change.
"Tax evasion" is clearly illegal.
"Tax planning" is clearly legal and acceptable.
"Tax avoidance" is using probably legal but weird methods to reduce (beyond any sensible amount) the tax burden of a company or very rich individual.