No, it isn’t a smear. It’s a generalization. Generally, it’s more true than not. Generally, birthers resort to personal attacks when they fail on the merits of an argument or simply get frustrated by facts.
If you’re offended by that generalization, perhaps you should speak to your group about refraining from such behavior. I’ve defended FR birthers off site. (You can Google it, if you like.) So I don’t feel a bit guilty about calling out the group as a whole for the tendency to make personal attacks.
True that!