Because it's an area. You can choose to take the centroid as coordinates. There are multiple data sources for an area with the same name. Depending of each one, the polygon representing it may vary. These differences can come from historical reasons, disagreement about the area coverage. So, the resulting centroid may change too.

Thinks about sea naming and coverage. Where is the "limit" between 2 seas for example? In this particular case, the name refers both to a New York quarter and a sea area (according to Wikipedia https://en.wikipedia.org/wiki/Jamaica_Bay). The tools can't guess.