[scott_s]

It's a personal attack, but not actually an ad hominem attack. There is a difference between "McDonalds has a bad business model because their burgers are gross" and "McDonalds is unpleasant to eat at because their burgers are gross." The poster's attack is of the second form.

[mail2345]

Still fallacious. To continue your analogy, this is like saying that all McDonald's stores have unpleasant food because of that one store. Yes, something should be done if it wasn't a one time thing, but no that does not mean the other stores necessarily have the issue(although they could).