If you want to communicate, you have to play the same game everyone else is playing.
If you don't believe in rationality and reason, why go on a forum and try making reasonable arguments? Wouldn't "squid purple smiley-emoji" be just as convincing?
Yep, I have been wondering about that person. Maybe some mental disability at play here that prevents them from seeing this obvious thing? Or maybe "I can use reason but when you do it, it is just wrong"? There are enough assholes around that do not believe others should have the same rights as they do.
The long and the short of it is, if you deny reason, everything breaks down. First, you lose all technology, because STEM is completely dependent on reason. Second, you lose society. Maybe you can keep a small cult going, but that is essentially it. And third, you lose the ability to predict and that means massively smaller survival odds. It really is the stupid choice. Even the big destroyer of minds, religion, does it only in a limited and targeted fashion.