As to your spotted flaws: firstly, it's obvious that people start their lives with 20+ years of being as net recipients of government transfers, and while the services you consumed may have been paid for at the time, those that paid them would now like their pensions, and a new generation of children need (apparently better) education.
It's unfortunate that three-year olds are not in a position to rationally choose to rather live in Somalia, and that they therefore become part of a social contract they never actually signed – but can you come up with a better arrangement? It's very similar with parents, btw.
Funny thing though: I just now notice that I've actually always shared your opinion, in that if you actually stop consuming government services, i. e. leave the country, I'e always taken for granted that you're henceforth taxed at your new residence (strange US rules nonewithstanding).
But Comcast example is obviously wrong because OP clearly intents to remain living in the US – i. e. using Comcast. And my arguments above actually make the case that you should pay severance and assume your share of the debt if you leave. But, considering the US is the prime beneficiary of smart 18-year old immigrants, it's probably in your interest not to change the SQ.
Oh, and only about 30% of the gov spending is in transfers, and most of that is SS and Medicare. While you could make the case that these lazy 80-year olds should stop sulking and get a job, some of them may protest and insist that they're just getting back what they paid into the system.