Arrogance
The last chapter of “I can decide what I believe or not, it’s my choice, I am free and I can have my own opinion about everything without any exception” is about arrogance.
Someone who knows about a specific topic and who shares that knowledge or even explains why they are wrong to those who spread false information is defined as being arrogant.
Oversimplifying things is not an alternative to hard work, deep knowledge and understanding of complex topics.
Being competent is different than being arrogant.
And yes, it’s better when competence is coupled with humility.