Are you plainly asserting that "this isn't an anecdote," and pairing that with a sarcastic statement that "this is an object lesson", meaning that it's not an object lesson, to reinforce your assertion that it isn't an anecdote?

Or are you plainly asserting that "this is an object lesson," and pairing that with a sarcastic statement that "this isn't an anecdote," meaning that is is an anecdote, to reinforce your assertion that this is an object lesson?

Or something else?