it's not exactly chosen to be the stopping point
also check out the video mentioned in comment which explains how the centrality, being in a big loop and being a high indegree node leads to this behaviour
https://www.youtube.com/watch?v=-llumS2rA8I
> 3. Stopping when reaching "Philosophy", or a page with no links, or when a loop occurs[4]
So, philosophy is explicitly chosen by the method as the "positive" occurrence vs its absence. If this is not the case, then wiki is doing a bad job explaining I think.