McDonald's functions as sort of public square, which is missing elsewhere in society, as the employees are to detached or inattentive to care if people are loitering too long. Same for Starbucks.
The author suggests the opposite, at least for McDonald's - the employees do care and are attentive to the needs of the people in the restaurant, and that's part of why the community springs up there. I'd expect McDonald's corporate policy is to hustle people along, and it's inattentiveness to that policy that enables the public square, not inattentiveness to the people in the square.
for what it's worth, I have not seen this at any McDonald's beyond the expected service of preparing the food.
The author of the article is a published author who writes about poverty and addiction - he links to a good excerpt from his book in the Guardian, which might better establish his bonafides for these kinds of claims: https://www.theguardian.com/us-news/2019/jun/05/america-dign...
I walked by the Starbucks in my neighborood recently and there were about 30 customers inside sitting at long tables. Every single person was staring at an electronic device. Maybe that's how a public square works nowdays.