I do wonder, though, how long this secondary meaning will last. Right now the dismissive connotation comes about because the phrase stands out, because it breaks the rules in order to be overly brief. If the phrase gets used more, and especially as a new generation never grows up not hearing it, it will not stand out anymore as an unconventional. It could just become grammatical. Without that element, it could easily lose its dismissive connotation.
This is kind of exciting to watch, in a nerdy sort of way. Language evolution doesn't really happen much in literate societies like ours, so it's neat that we have an example unfolding before our eyes.