First let me acknowledge your changing the subject or at least expanding discussion. Not saying anything wrong with that, just stating it as fact, since the portion of the thread pertained to Trump. Perhaps it's a tactic or maybe you just dont have anything to add within scope. That said, I acknowledge that the Trump conversation is too off topic from your original post.
... and to hear a liberal criticize conservatives for lack of precision and nuance is ironic. ?
Ooh the dirty L word (or maybe I am misunderstanding your meaning). So whatever follows falls on deaf ears I suppose, but as long as I am what you say, at least in your mind, and seem to know "what is proper" I might as well "persist" and play the part.
Since we are talking about meaning, perhaps let's start with the definition of irony: the expression of one's meaning by using language that normally signifies the opposite, typically for humorous or emphatic.
Out the gate, we start with ad hominen. Or maybe that's just the oversensitive PC liberal coming out.
The proper question is, "Who decides what that meaning is?"
The answer to your question as who decides what meaning is? I would say the lowest common denominator, the individual, assuming said individual is a rational adult capable of making such judgements and decisions. That said there are social norms and consensus that that form and influence meaning.
For example, do the words "freedom of speech" mean the freedom to express your opinion even if such opinion is in conflict with the view of others, or does freedom of speech mean that intellectually energetic liberals on college campuses should be allowed to cancel speeches from speakers with whom they disagree?
What are you arguing here? That because you believe me to be liberal I justify the cancellation of speeches from speakers with which I disagree? Or because you believe me to be a liberal, I support what these "intellectually energetic liberals" did? Your following questions are just a repeat of the same straw man.