That's a generalization. In some (maybe most?) situations it won't hurt anything, but there are certainly cases of people getting killed because of an airbag.

I'm of the belief that wearing a seatbelt alone is more than adaquate and the benefits of having an airbag don't outweigh the risks as long as you always buckle up. I'd love to see some data (where seatbelt + airbag did better than a seatbelt only) to the contrary though. That's not even taking into consideration a more advanced restraint system.