Subjectivist or Relativist Fallacy

The subjectivist fallacy occurs when someone claims that something is true for some people but not for someone else, when, in fact, it is true for everyone, as demonstrated by empirical evidence.

The shape of Earth is not a matter of belief or preference, but an objective truth from observations that applies to everyone. It is impossible Earth is both spherical and flat at the same time, depending on what we prefer or believe.