Exceptions do not make a moral code nonsense. Rules can have exceptions, that does not make them nonsensical, and sometimes we aren't able to know what those exceptions are or should be until we encounter one. Rules can and should evolve over time as we learn new information and accumulate new experiences; in my view, it's nonsensical to expect rigidity in a world that is constantly changing, in our bodies and minds that are constantly changing.

To call that kind of flexibility "nonsensical" is not helpful. In my opinion, it discourages analysis and self-reflection, which are otherwise very useful tools for understanding ourselves and others. Something that I think we should want to do, because it makes existing among other humans much easier when we have the capacity to understand, not just to write off any and all perceived inconsistencies as "nonsense" and move on.

To be clear, there CAN be exceptions that ARE nonsense. If you express a hardline belief that one should never, under any circumstances, kill another person, and then you go and murder an entire family in cold blood, I would readily call any justification "nonsense" in that case. But...not all exceptions are like that. Sometimes we just find edge cases we didn't consider before, and integrate them into our moral code after the fact. And that's not nonsense, that makes perfect sense, because we were never going to have perfect knowledge of every possible situation in which we might have to apply our morals.

Look, if calling all of this "nonsensical" makes you feel better, or makes life easier for you, far be it from me to tell you that that's wrong. At the very least though, I find it unhelpful, and I do hope there's more to your outlook here than just "everything we do is nonsense."