Also, change takes time. There's a digestion process. Of course some people are not interested in finding truth and simply cling to their own opinion.

My advice was meant to be interpreted in a more holistic sense. It is true that occasionally, people have had their minds changed by reading an internet discussion. But most people are more likely to change someone's mind by speaking to people they know in the real world, than they are by contributing to the noise on the Internet.