I think you present valid points. I am not so sure I agree with #2. You can also write to educate people and keep them informed on something they don’t know or can learn from a fresh, different perspective.
The two that go hand-in-hand are writing more and not taking criticism personally. I think that’s part of the beauty of writing. Everyone has a voice, but not everyone has to agree with it. The more you stir the more effective you can become as a writer even if it means irritating a few people. You have the power to say what you feel about something and voice it on an open platform!