Adults can support themselves, children can’t. They also don’t receive money directly from the government.
I can’t believe you thought that was a good question.
The issue is that you believe that society can be conveniently divided into ‘productive’ and ‘unproductive’ categories, often defined by characteristics that aren’t necessarily predictive of their economic status (i.e. whether they were born in this country) and often splitting hairs over what kinds of government expenditures should be taken into account (welfare payments bad, free schooling good etc).
Like most topics on here, everyone agrees with the central point that our welfare system (or asylum system, or healthcare system etc) is in need of reform. But the attempts to hijack the process in the name of advancing pet projects on immigration etc mean we just go round in circles until we’ve all been bludgeoned into submission by your extended essays.