I get the feeling I am missing some info (Like what is meant here by Data Center Networks) thats preventing me from understanding whats happening here. I am guessing that this falls outside of the traditional rack/colo paradigm and has more to do with hyperscalers.

It's much larger but fundamentally it's not that different. In each rack you have one or two switches. How do you connect those racks to each other? The standard answer (simplified) is centralized spine switches but AWS discovered that a random network where the rack switches connect directly to each other is cheaper.

AWS hasn't published all that much about their network, but we know they use a high-radix folded Clos fabric because they mention it in their paper about Scalable Reliable Datagram. If you want an overview of the folded Clos fabric, try reading Google's "Jupiter Rising" paper. https://dl.acm.org/doi/pdf/10.1145/2829988.2787508