They deserve sympathy, but not necessarily the same care. For maximum societal benefit it may be that it's better to spend more on kids in school than schizophrenic meth addicts. We live in a world of scarcity, we can't do everything.
Besides, the school system needs more than just money, just like the "homeless problem". I don't feel comfortable passing judgement on one class of people vs another solely because of the circumstances they were born into.
The part 'vs another solely because of the circumstances they were born into' from the parent post does not reflect what the GP post actually says. The GP was solely arguing on the practicality and the costs and benefits of doing it; solutions to problems have trade-offs, it is no good wishing them away.
That said, how the homeless are treated in a lot of rich nations today are a complete disgrace. Increasing a well off persons well being is worth far less than increasing a not so well off persons well being IMO.