Is what my husband has just said to me when I tried to raise an issue with him about my SC.
Short version is that I've noticed 9 year old SC doesn't eat much in the mornings before school or before weekend hobbies. He'll have something like an apple for breakfast and then go off to school. He's very slim and I personally don't feel like he eats enough generally.
I mentioned this to H this morning and said I don't feel it's my place to insist he has more in the mornings as I'm not his mum but thought I should mention it. And his response was 'you can say something, you're not his mum but you should care'....
like duh... That's why I'm saying something??
Long version is that I feel and have felt in the past that H parents in a way I wouldn't choose to myself. Not with all things but with some. And I felt I was becoming the only one to 'nag' my SS to do what I felt was perfectly normal things like tidy up after himself for example, put wrappers in the bin that sort of thing and other things I felt were better for him like eating and drinking more etc.. I didn't want to be the strict one in our home so I just took a massive step back from it all and let H crack on.
This is why I brought the issue to him rather than saying something to SS myself. Now I've been accused of not caring that he's not eating enough... 
Wtf you literally can't win!