Why does it bother me when it’s none of my business

A girl that I used to be Bestfriends with abandoned her two kids because she was on drugs. Her father now raises her oldest two. She also lost two babies while pregnant because she couldn’t stop doing drugs. She got pregnant again and shortly after met a good man that said he’d help her raise the baby. They got married before she had the baby and now they have two kids together. There was a go fund me page being shared not too long ago because her father isn’t getting any help from her or the state with her kids. So he’s struggling big time and lost his house. I work in retail and I saw him come in with her kids. They’re so cute and polite it just melted my heart. I know it’s none of my business but I feel so bad for her two oldest and her father. If she decides to abandon two kids why does she get the right to keep having more. Why didn’t she come back for them after she got her life together?!. My hate for her grew so much that I had to stop being her friend. I just can’t stand it