The problem with that interpretation is that you can’t have “libraries turning into drug-infested, libraries turning into sex dens.” because “drug-infested” is not a noun phrase a library can turn into like “sex dens” is. I also tried misinterpreting this comma as a comma between two adjectives, which doesn’t work because “sex” is not an adjective. Maybe “Libraries turning drug-infested, into sex dens” fits your interpretation better. Does it?

As a side-note to your helpful link, I really dislike it when headlines use a comma in place of an “and”. Like, use “&” if you really must.

Print is not exactly the main way people read the news now anyway, I think they can spare the pixels!

semicolon