Yeah, I’m not arguing that time can be considered a fourth dimension, or the relationship between time and space.
But the comment about 4D being hard to comprehend was referring to the idea of a fourth spatial dimension (as we could comprehend such a thing). Obviously, we don’t have a hard time comprehending time (at least superficially), so the comment about it being “comical” is pedantic and has strong “AKSHUALLY” energy.