Suppose their definition for abject poverty is: having an income equal to or below the median income. Yes, they would be right. Is it a problem that they are right?

However, you would also be right in agreeing that having an income equal to or below the median income equates to half the population, so you are wrong to think that only they can be right. Of course, that assumes you have used my definitions for these terms and not your own. It is likely that, once we are updated with your definitions, that you were right all along. What are your definitions for the terms you have used?

That's the beauty of discussion. You don't need to guess. You can ask!