Earlier quoted context omitted.
You don't have to worry about that BS if you use free software alternatives either. Plus you get to contribute to an alternative ecosystem that is also a lawful and moral alternative (Because piracy is both illegal and immoral in many circles.)
How do you contribute by using free software? You contribute if you give something, mainly coding or money.
For example, in one of my last job (I'm a freelance), I could get paid full time to contribute to open source tools because the guy taking the decision heard about PostgreSQL and open source somewhere. If that guy has only heard about Oracle, the same work would have gone closed source.
If the person responsible for the office solution of a school heard of open office from you, you did help a lot. Because many times, big open source users will invest in open source, in form of support, custom development or just sponsoring.