It's not a criticism so don't take it as such. I have children myself.
But it's all about them. I've noted my friends' reactions to the Manchester attacks have all been in a way about them or their children really. "How awful that little Sophie / Freddie /Millie is growing up in a world like this' and 'thinking of the parents who don't get to kiss their children good night.'
It's not a bad thing, it's a sensible thing as putting your own children first ensures the survival of the species but what does interest me is that single people are often put forward as selfish ones when I think it's more likely to be the other way round.