Outrage Over Woman Who Breastfeeds her son and his friend

This Pennsylvanian mum,Jessica Anne Colletti has sparked outrage over the Internet after she shared a photo of her breastfeeding her son and his friend who is Jessica's friend. Her sons friend has also been identified as a son to Jessica's friend.

She wrote:

"My son on the right is 16 months and my friend's son is 18 months. I watch her son while she works and have been feeding them both for a year! So much love between these milk siblings, it's a special bond between us all #MilkSiblings. Breastfeeding my friend's son came naturally to me.  I started babysitting him when he was 5 months old and the first time she dropped him off to me I asked permission to nurse him, since I was already nursing my 3 month old.  She responded with an enthusiastic yes, because he was having issues with the formula his previous sitter had been giving him.  My friend struggled with breastfeeding in the beginning and succeeded for 9 months.  She was always very happy that her son had the nutrition and comfort he needed while she was working.  Being able to breastfeed her little boy has created a special bond between us all, a bond I will always cherish."

Is this not unhealthy?