This was a big point of its critics: the City was ostensibly a partner, but had very poor literacy and so Sidewalk Labs was essentially taking lead. When the City did seek their own third-party supports, they naively sought only supportive tech partners. There were whole classes of consultants they never engaged with, as they were naively focussed on sealing the deal.

I read it as maybe something like Bay of Pigs groupthink (for which the term was invented to explain): https://www.youtube.com/watch?v=glUUmsBb_58

They lacked certain diversity of views that would have allowed them to better see where this plan was flawed. They got caught up in their good intentions.