Some of that, sure, but I'd imagine more often it's just "realized they're wrong (consciously or subconsciously), try to save face by derailing conversation".

Some of that, sure, but I'd imagine more often it's just "realized they're wrong (consciously or subconsciously), try to save face by derailing conversation". There is of course flipside of it, "is actually right but can't explain it properly, either by own ineptitude or target audience's ignorance".