I only have anecdotal evidence but anecdotal evidence I do have.

1. There is a McDonalds that was near my Elementary school, actually used to be my favorite place as a kid and it was the place where I would socialize with kids from the Boys and Girls club about a block or so away. Even though there is a large municipal park across the street and numerous bars and clubs and restaurants around that area, you could still see people actually meeting, or just hanging out there. I have no idea what this particular McDonalds* is like nowadays, but I've heard through the grapevine it's become the epicenter for numerous drug problems in the neighborhood, which are only complaints you started hearing about once Whole Foods opened up across the street. I suspect that it is neither the epicenter of the drug problems in the 'hood given exactly what that particular neighborhood is famous for, and it is famous, nor do I think it has actually changed at all in the last 20 years.

Most likely the only thing that changed is there are a lot more affluent people in the area which are taking issue with having a symbol of poverty in their presence, across the street from a supermarket that just so happens to symbolize their wealth.

2. There's another McDonalds I would walk past every day on my way too and from school. Often it was faster than waiting for the trolley bus as the trolley part of the bus would often fall and slow everyone down back in the day and my route to Middle school and later High school was an L-shaped route. Eventually the local MTA replaced the trolley buses with an updated model and the problems were at least reduced, but not eliminated.

Passing this same McDonalds you could make a few observations. First, the people there were of two particular demographics, and the housing nearby was Section 8. Second, just pass the McDonalds there would be a park, nothing fancy, just a bit of grass and some benches in the middle of the block where quite a few locals would socialize. Third, just past this park was a rundown boarded up church with empowering messages targeted towards a particular demographic. Directly across the street from this rundown church was a police station loaded up with surveillance cameras, even more than I observed around other police stations at that time. Going back towards the McDonalds but across the street now, there was if I recall correctly, a salon or a barbershop (both? been a while), a liquor store, a pizza place (these might have been one and the same) and apartment buildings. Not too far away in either direction were two community centers.

What's my point? Humans are social beasts, we gather together over hot beverages and food, whether our incomes are large or small. More affluent people have more options for this, but much of the time people like to go out and gather with those around them, particularly when they have fewer options.

Advert or not, the thesis of this article is not wrong. Go to low income neighborhoods and find a McDonalds, get yourself a coffee or burger or whatever and just sit down and watch people. Go to areas where McDonald's exists but where the surrounding area is being gentrified and watch the looks of disgust on peoples' faces as they pass through and by poverty. Coming from a different sphere of life, it's pretty hard to read an article like this and not think this is just a paid advert, and I understand the reaction, but I would not doubt that for many communities, this article is basically the truth.

* Given just who many of the people on Hacker News are and the metro areas they tend to reside in, in numbers anyway, there is a better than even chance you can figure out exactly which area and which McDonalds specifically I'm talking about.