Are they interpreting it as a question of signalling without even reaching the point of evaluating it as [a propositional] statement?
That is more or less the human default. And of course you won't get them to admit it if you ask them "are you just signaling?", because that very question and its answer have signaling value themselves.
This isn't a deliberate deception; I'm convinced that most people's brains process language first and foremost as signaling-transactions and not as propositional content.
A article in the Atlantic, linked to by someone on the unofficial LW IRC channel caught my eye. Nothing all that new for LessWrong readers, but still it is good to see any mention of such biases in mainstream media.
I break here to comment that I don't see why we would expect this to be so given the reality of academia.