It's a bit unfair though Oblo
There are any number of adults, and it's possible I am one of them, who don't like to give too much head space to the very real suffering happening in the world. I get emails form Amnesty, who I support as a charity financially and will sign petitions, but to dwell on it, and certainly in the context of my own good fortune, upsets me pointlessly as I really can't do much beyond financial support.
Then there's also an element of what makes someone 'lucky.' I certainly had a very materially privileged childhood. My parents were older ones who had tried for years for a baby then when two came in rapid succession my dad - originally the one who had been by his own admission unconcerned about whether he had children or not - discovered he loved being a parent, my mum however did not. My memories of the time before I turned five are patchy at best but apart from some time with my dad, they aren't happy. I was largely left to play on my own or handed to relatives, who didn't really want me either. I now recognise my mum was very depressed, or possibly even even more severely mentally unwell than that, and she did love me in a way. All the same, it was a confusing message for a small child: you are lucky, lucky, lucky - yet your own world is so tiny as a little girl or boy anyway you can't really compare it in any meaningful way to another child, and the 'lucky' comments lead to misplaced guilt and pressure not to be sad or unhappy because after all, you're 'lucky.'
I think if what you (general you) ultimately want is a balanced, compassionate, sensible and kind child then that doesn't come from lecturing them about their good fortune in being the particular sperm and egg that came from loving parents and certainly not for preschoolers! I think books are a great way in here in a gradual and non-threatening way (Jacqueline Wilson are a good choice for older primary, for example) and things like getting a new family pet can be a good way to go to a rescue centre and talk honestly about why some of the animals might have ended up there, passing the food bank collection point in the supermarket, witnessing a homeless person and so on.
But there is a difference to, say, encouraging your child to choose something for the food bank when you go to Tesco and having a chat about why different people might need to use it, and lecturing them about THEIR relative good fortune in having a trolley filled with food!