Concern for the child, vilification of mothers, I don't see the difference in many of these posts. I have lots of concern for foetuses exposed to any negative situations but that doesn't automatically mean the mother is a neglectful, selfish, abusive person. I am not defending smokers, I'm defending mothers.
Specific to smoking there is a whole world of compounding factors behind why people smoke in the first place and in the majority of cases, though of course not all, these come down to situations beyond their control such as economic status and domestic situation. Sometimes smoking is the lesser of two evils where it is the thing keeping a woman sane who might otherwise doing something very serious due to the stressors in her individual life. Sometimes it's simply ignorance of the effects. Whatever any of you on here might think no, not everyone really does fully understand the potential implications, even for themselves. I see all the time even on here that even in the face of hard and fast scientific evidence people will usually follow what their family and peers say and do. Particularly in pregnancy and parenting anecdote is king. It's simply human nature.
It's not a defence of smoking it's a defence of understanding that not everyone is the same, not everyone's understanding is the same and not everyone's situation is the same. Life is complicated and criminalising people for their lot achieves nothing.
You say it's not a legal issue but the rights of an unborn child is a legal issue. And you must accept that morality is complex. What's reprehensible to you is not necessarily so for others. There is no right or wrong in morality, it's a social construct. The thinkers of the world explore situations and fight for change. Over time some gain acceptance of the non-thinkers but societal acceptance is not the same as 'right'.