first of all the biggest issue i have with that is that they introduce a completly healthy and fit brother of the harlot that said harlot is providing for. why isnt this brother providing for his sister? why is he allowing his family member to do such activities when he could be making up the difference? it smells of some "charlie and his 4 'bedridden' grandparens" crap.
and second there is a very important thing you missing about developing nations. the reason that developing nations resort to such things isnt actually poverty, how do we know? because we dont see such a thing in tribe societies that still exist. tribesmen provide for their women based off what they hunt and sleeping around is an easy way of getting yourself killed by your husband(or somtimes husbands) so what is the actual reason its so common in developing countries? corruption. if you dont have friends in government then the tax rates will not hold back and simply living your life normally isnt an option but there will be a shady man who knocks on your door and says that a women helping out the local red-light district would really help in making mr taxman forget about them. and if its not the government then crime elements might make demands for a women for them to be left alone. in other words harlotry in developing countries is out of safety, not poverty.
which then brings us back to this manga. the 'government' is human centric and wouldnt want to force its population into such a circumstance, and the only crime element theyve shown is trying to STOP the harlotry. so either these harlots have a bunch of 'bedridden' leeches they need to feed like the brother thats introduced, the government; which is run by their savor in that chapter; is alot more corrupt then the manga is letting on atm, or these harlots are simply whores that i cannot sympathize with