Wrong pelly. Your assertion of ad hom fails to meet the minimum requirements. Try again.
The definition:
"Ad hominem circumstantial points out that someone is in circumstances such that he is disposed to take a particular position. Ad hominem circumstantial constitutes an attack on the bias of a source. This is fallacious because a disposition to make a certain argument does not make the argument false; this overlaps with the genetic fallacy (an argument that a claim is incorrect due to its source)"
Your post:
"” Who made the post should have been your first clue.”"
An ad hominem has as its subject a person, rather than his argument. Since you insist that your post doesn't meet the definition of ad hominem then you should be able to identify the subject of your sentence. What is it, exactly?