You have the red dots indicating a pedestrian route that does, indeed, exist but it is not possible to generate a pedestrian route from Onslow Road to Pratt Street by this route.

I physically used the rat path (what I call this pedestrian route) today. I am literally just trying to find a map that can tell me how far I walked. Google Maps does a bizarre deviation so it doesn't work. And OSM and its derivatives doesn't let one use the rat path to get from Onslow Road to Pratt Street. It's incredibly frustrating.