The point is that taxes can be allocated to things you do not directly benefit from.

I am aware of the fact that states do not subsidize states, but actually drilling down to the taxpayer level makes the argument even stronger. As long as there are regional differences in benefits from federal funding, you get the same effect.

The farming states benefit disproportionately from farm subsidies. Oil producing states benefit disproportionately from oil subsidies. And states near DC benefit disproportionately from federal bureaucracies.