I really don't know what else to add. But let's go with this: Is it true or false that the convention does not permit certain interpretations? Is it objectively true or false? If it is not objectively true or false, in what consists the convention?
It is clearly true that convention does not permit certain interpretations.
But what does that have to do with objectivity?
As I have already argued, convention can be violated.
Objectivity presumably cannot.
The convention consists of social accordance on a set of rules.
These rules change over time, and over space.
Objectivity should be stronger than this, dontcha think?
Sorry, I was not convinced.
Then permit me to ask which part of my argument failed to convince you.
For example, I mentioned that Americans cannot say that
Sherlock Holmes lives on XXX Y Street
unless he literally lives on top of the building.
Is there some objective truth there that American English speakers are missing?
What about my questions highlighting how language is interpreted differently by different people at different times?
What about tautologies? Aren't tautologies a clear case of truths that are (a) objective and (b) artifacts of language?
Tautologies are most definitely NOT artifacts of language, as I understand them.
They arise from a study of formal logic, which is something entirely different from (and, dare I say, tangential to) language.