There are several problems with arguing. The main one is: it never works. People just look for confirmation of their own theory.
Some specific problems: People remember evidence that agrees with their theory, and forget where that information comes from. Particularly, when conspiracy theories are attacked, any evidence is discarded as being part of the conspiracy. In a similar way, evidence against creationism is denied by divine miracles, often to the point of absurdity.
Another problem is the variety of theories. If I try to defeat a particular theory, let's say Astrology, I could point out a bunch of problems. But most Astrologists don't agree, and they would probably agree with much of my criticism, saying that those other Astrologists are "doing it wrong".
Anyway, occasionally people do change their mind in science, but even that is rare. Most scientific (and social) progress is made not when the older generation has a change of heart, but when they grow old and die.