I think this is quote is really being taken out of context.

I wrote that passage as a response to /u/Starkren saying:

...I don't understand this desire to dole out unsolicited criticism to people who probably don't want it.

So the passage outright dismiss unsolicited criticism. as I pointed out in my OP, the act of writing fanfiction, in of itself, is an act of commentary. It is a critique of the canon. It's a reaction to the original work, in written form. Now, we can debate this if you like.

Regardless, I recontextualized the passage so that the double-standards become apparent when someone is fine with writing fanfiction (regardless of quality—good or bad) but is vehemently against concrit.