That's correct. Deliberately restructuring your activities beyond common sense in order to reduce taxes even further, however, is legally evading them, by the normal definition of the English word "evade".

If you are running a business and someone points out you can reduce taxes by registering a corporation, that's normal - most businesses are some type of corporation.

If someone points out you can reduce taxes even further by registering an Irish subsidiary and sending them license fees, that's abnormal, and now you're using trickery to avoid taxes. UNLESS your business really does do R&D in Ireland at an arms-length subsidiary which charges license fees. In that case, the legal structure mirrors what is actually happening, so it's fine!

> however, is legally evading them

In tax law, this is considered avoidance, ie. you are avoiding overpayment.

If you so much as use any tax preparation software, you are actively avoiding overpayment of your taxes.