alt Hacker News> have some individual incentives to develop services offered to the poor
I never said that wasn't the case but historically that "some" was never sufficient. On average people are rational and selfish to a larger extent than they are altruistic.
> taxes in that pursuit are illegitimate under a theory taxation happens by the assent of the people
Well the whole concept of an organized society falls apart if individuals can personally freely chose which laws to obey and which taxes to pay. You have to have a balance based on a reasonable consensus, otherwise you end up with totalitarianism or anarchy (and in that case the people who have the means and resources to do that will establish alternative power structures and will end up subjugating those who do not AND also outcompete those how have the means but are unwilling to do the same).
No, I'm not talking about picking and choosing for a voted tax. I'm saying it can't be true most people don't want to help fund the poor if the majority are voting to tax themselves to fund the poor. Clearly under anything remotely resembling the Australian representation of what they claim their representative democracy is, the majority of people already decided they individually are incentivized to help the poor develop infrastructure.
It can't simultaneously be true that most don't want to help the poor at their own cost while also the tax has been legitimized by the majority wanting to help the poor at their own cost. Only individuals or representatives elected by individuals can vote and if their incentive was to not help the poor then they'd vote not to and that would be that.