The argument that paying more taxes than you strictly have to is a "voluntary donations". If you can legally (ab)use loopholes in the tax code to pay less taxes and choose not to, that is an active choice you are making to pay more taxes than necessary. Furthermore you could even argue that as a company it's not even 'your' money, but your shareholder's, and as such you have a duty to them to pay as little tax as legally possible.