Interpretation...is it valid critique?

[rayheinrich]

A word is never a cliche. Identifying pi is also not cliche it is identity. "Art is subjective" isn't true identity it is figurative - thus cliche.

Disagreement does not change a subject/word meaning/statement into a
cliché. While I agree that assertions: "Art is subjective", "Abortion
is murder", "Clowns are evil", "Pi is equal to 3", "The world is spherical
(not true, BTW)" may or may not be cliché; calling a debatable assertion
a cliché is quite often a rhetorical ploy that attempts to discredit an
assertion, not by evidence or logical reasoning, but by associating it
with an undesirable quality of some sort. Which is what I think you
are doing in this instance.

And of course words can be clichés: "Twirk" became a cliché overnight
thanks to Miley Cyrus's performance on the 2013 MTV Video Music Awards.

While I certainly think "pi" can be construed as a cliché (it's a stretch,
I grant you); you may disagree. Do you know why?
(here comes another cliché):

Clichés are subjective!