I think you're being overly generous. Anyone can make a simple error, but it takes a special kind of person to screw up in such spectacular fashion as in that post. This writer wrote but fourteen words, and in so doing, made one blindingly obvious grammatical error (the aforementioned "an writer"), one capitalisation error (self-publishing is NOT a proper noun), one style error (one may place a space on both sides or on neither side of the "/"), and one logical construction error (the statement and question were linked by punctuation, but bore no contextual relationship to each other).
Protip: when claiming - in writing - to be a writer, it's usually a good idea to proofread one's own work prior to publication.
Disclaimer: Sigg3.net may not be a native speaker of English. If that be the case, it's not such a spectacular screw up, as I am quite certain that his command of English is far better than my command of his native language.