Observations are inherently a posteriori, not a priori, this is true. However, "universal observation" is not the same as "objective" or "a priori". I'd call the experience of suffering a type of universal observation, but it's not an a priori statement, and it's certainly not objectively evaluable.
That said, the phrase remains mostly meaningless without more context; I'm certainly not trying to defend the phrase itself.
That said, the phrase remains mostly meaningless without more context; I'm certainly not trying to defend the phrase itself.