That’s the only legitimate defense for having to tag your sarcasm I’ve ever read.
Back in MY DAY, nobody tagged their sarcasm on BBS or IRC and we ALL UNDERSTOOD AAAAA (but srsly for folks who have trouble with tone you’re fully right.)
What are you talking about? Even usenet in the 80s recommended using emoticons to mark sarcasm/joking remarks.
Avoid sarcasm and facetious remarks.
Without the voice inflection and body language of personal communication these are easily misinterpreted. A sideways smile, :-), has become widely accepted on the net as an indication that “I’m only kidding”. If you submit a satiric item without this symbol, no matter how obvious the satire is to you, do not be surprised if people take it seriously.