about baby slings not being safe. The slings they are talking about are the "bag like" slings, and carrying baby in the "c like" position where mom carries baby near her belly, in this position baby's chin may rest on chest, obstructing baby's face. Don't use these slings.
Babywearing, when done the right way, is beneficial for mama and baby. Educate yourself. Babywearing (the right way) is so special.
Here are some links to learn how to wear baby the right way.