"Meaningless" doesn't mean everyone fails to find meaning, it means that there is no general consensus on what it means. As you pointed out before, everyone holds their own pet definition. It means something to most everyone, but there isn't a shared understanding of what it means across the general population.

While it is true that words often have multiple meanings while remaining meaningful, they do not have multiple meanings within the same context as is the case here. I am surprised that wasn't obvious to you. Hey, on the bright side, at least you got to learn something new today.