That's actually the entire point they are trying to make. They don't make an enormous difference to your welfare. At least not when compared to someone making $15k / year and trying to support a family. You really can't understand what it's like to not know where your next meal is coming from unless you have been there.
I understood the grandparent's point to be that the taxes contribute to the tax-payers welfare in the form of keeping society more-or-less together, which is a huge benefit. Maybe I misunderstood though.