Well you prompted me to check whether I understand what "absurd" and "ism" mean because it seemed pretty apt to me. Still does after checking, at least for the standards of a comment on an article, as opposed to say a language semantics journal.
To clarify, the original use here was "absurdism may now be part of our youth culture", which is certainly something one could argue, but I'd strongly disagree with.
If he wanted to use the definition you're constructing, I think he should have said "little absurdisms like this are a common part of our youth culture". That, I could agree with.
I didn't realize this would be controversial. I meant "absurdism" in a non-philosophical sense. The way you phrased it -- "little absurdisms like this are a common part of our youth culture" -- sums it up perfectly.
Being popular gives us the "ism" part, by definition 3 at http://en.wiktionary.org/wiki/-ism :
"a tendency of behaviour, action or opinion belonging to a class or group of persons; the result of a doctrine, ideology, principle, or lack thereof"
The "absurd" part also fits pretty well: http://dictionary.cambridge.org/dictionary/british/absurd "stupid or unreasonable; silly in a humorous way"