While ad hominem is usually bad, I don't see the problem with using it in response to anecdotal evidence. If your argument is "I, personally, can't run my business while paying employees an average wage!", then "your business was spiraling downwards while before the downturn and well before healthcare reform and wage bumps" seems to be a decent response.

Similarly, knowing someone's background is pretty crucial for an op-ed. If the piece is being sold as "I'm a typical businessman, and Obama's policies are keeping me from hiring people", then it's important to know if the businessman in question is typical, or if he's politically connected.

Edit: Typo'd "solid" for "sold".