These (i. e., the statements of the Nicene Creed) are all empirical statements about reality: they are either true or false, even if some are hard to investigate.
These claims, of course, absolutely conflict with those of other faiths. Jews, Muslims, Hindus, and Sikhs don't recognize Jesus as the Messiah. Muslims believe that those who do so will spend eternity in hell. Doesn't choosing among such faiths require a way to evaluate whether this dogma is true?