Because that’s not how human nature works. Trust starts to weaken with scale. In a small village you’d be accountable and your life would be made harder for taking advantage of someone, but if you don’t know the person and will never see her again, people feel very safe to risk and make an extra. The consequences of social life differ widely in small and big scale. Plenty of old tales of travelling merchants selling junk for gold, profitting on ignorance.
This is the kind of comment that I would expect from a Solarpunk, a critical, curious and hopeful hint to start a discussion towards a positive productive possible outcome, instead of the regular neo-rural cottagecore luddite cryptophobia rants