Well, you have to draw a line somewhere between ethical tax minimization and unethical tax evasion. Where do you draw it?

This is a continuum that stretches from clearly illegal schemes through hazy waters, into calm water like deducting salaries and cost of goods sold from revenue and paying tax on the balance. For individuals "tax avoidance" includes deducting charity contributions and taking advantage of things like deductions for dependents. If that is not "unethical" to you then you need to make a distinction between tax avoidance and tax evasion.

Many people believe "is it legal" is a good line to use. You may differ on that, but you can't escape the dichotomy.