There are 664,435 reported abortions in 2013, compared to about 33760 firearms homicides. There is a scale difference but not in the direction you anticipated.
While that's surprising, that doesn't quite contradict my point: a firearm has greater leverage.
The main point is that while almost everyone will agree that murder of humans is undesirable, not everyone will agree that abortion is murder (_even_ in the United States), which means that it is not categorically clear that the outcome of abortion is a negative one, while it is clear that the outcome of a shooting is a negative one, and therefore there is a stronger public interest case in applying commercial pressure to sales.
The main point is that while almost everyone will agree that murder of humans is undesirable, not everyone will agree that abortion is murder (_even_ in the United States), which means that it is not categorically clear that the outcome of abortion is a negative one, while it is clear that the outcome of a shooting is a negative one, and therefore there is a stronger public interest case in applying commercial pressure to sales.