Well, why is it so imperative that we talk about the costs if we're in a agreement that there's a net benefit? Perhaps I am projecting, but generally when people are at pains to point out that things are not free and there's a cost, what they mean is that there's a net cost to society (or think that there is) and that the money would be best spent somewhere else or not collected at all. When you lead off with a complaint that the money from social programs was extracted from you by 'coercion' the implication is that you're being forced to pay for something people should have to finance themselves.

I really don't get how you think this is a net good move but couch your argument in the form of a complaint about the government taking your lunch money. By definition, a net good is economically less costly to provide than to withhold. Even over the very short term (ie within the same fiscal year) I suggest that the opportunity cost of supplying the baby box is no more, or possibly lower than the costs of autopsies and lost productivity resulting from a higher rate of infant mortality.

It just means they feel like the other party is forgetting about the cost. For example, if I hear my friend raving about this new phone that only costs 99 dollars, I might remind him that it would require him to upgrade to a data plan that costs 20 dollars more per month. That doesn't mean that the phone isn't still worth buying, just that it's not as cheap as I think he is imagining it to be.

Honestly, and especially in the case of public goods like the baby box discussed here, I think people are perfectly well aware that they don't fall out of the sky or grow on trees, even if they can't articulate the entire cost-benefit structure at the drop of a hat. But people who say the cost is being forgotten usually complain that it has to be picked up by 'the taxpayer' (meaning themselves), as if the expectant parent(s) had no history or prospects of ever paying taxes themselves.

Intentionally or not, the implicit suggestion that the costs are being picked up by someone else is rooted in economic stereotypes that remain widespread in the US despite a lack of supporting evidence.

http://en.wikipedia.org/wiki/Welfare_queen or for a more current example: http://articles.washingtonpost.com/2013-04-09/politics/38405...

There's a net benefit to eating out every night (it's tasty and we don't have to do dishes), but my wife and I still consider the costs.

Just because something produces a net benefit does not mean that there are infinite funds to allocate toward it.

Those are benefits. A net benefit means it's more economically efficient than the alternative - which might be true for you, but isn't necessarily so.