Breastfeeding

I have to start by saying, I am all for breastfeeding, I tried to breastfeed with my son but that only lasted 6 months because I couldn't produce and he didn't latch properly ANYWAY.

My SIL is part of this group on FB called semi 'crunchy' parent group in our area, and she added me. So someone posted a link to an article about breast feeding preschool age children, 2-6yo. And they all see nothing wrong with it they actually wanted to shame the people who don't approve. My SIL posted saying once baby number 2 comes she will tandem breast feed her 2yo whom already weaned himself at 10m. What are your feelings on extended breastfeeding? And am I weird for feeling that her breastfeeding her already weaned 2yo is weird?