An unfalsifiable theory is not necessarily wrong it just isn t of much scientific use if it can t be tested. Some people who advocate unfalsifiable theories are just playing it safe. Some are shams. They seem to be right because they have carefully crafted a theory that can t be shown wrong. But usually, an unfalsifiable theory is little more than hot air and contributes little to understanding.
Some people believe unfalsifiable theories because they have just never thought about it.
This is one way of defining science it is statements that are falsifiable. And we believe the ones that haven t yet been falsified. Unfalsifiable statements have no meaning, or aren t worth the time and effort, or are outside the realm of science.