Because that other person is too subjective or biased. You can make a completely logical point and he will not cooperate in any way. It is the same as arguing sports like Lebron vs Kobe, you will never hear the end of it.
Wouldn't what you described be considered a debate? Both think they are right so they talk about it to get it out in the open. Maybe, just maybe, one or the other might just see the point in question in a different light. But just to let you know, Topgonzo has helped a lot of people here and is a credible person. But just because one person doesn't agree with another, logical or not, right or wrong, doesn't make them subjective or biased. It makes them passionate.