Why are crossroads infected?

Why are crossroads infected? The infection spreads and the crossroads are an example of this. This. Also, mechanically, it is because you either defeated the Broken Vessel, or you killed one of the Dreamers. Once you do either of those things it triggers the Infected Crossroads.

The infection spreads and the crossroads are an example of this. This. Also, mechanically, it is because you either defeated the Broken Vessel, or you killed one of the Dreamers. Once you do either of those things it triggers the Infected Crossroads.