So they built a new product to a competitor's API spec? There is nothing wrong with that, the API itself is a plug - you need to implement the backend to compete.

It is super lame and dumb to have ripped off their doc, but the API format itself is not an issue to me. If I were going to implement a competitor to Google Maps, it would make sense to copy the Maps API so people can migrate seamlessly. That is the nature of SaaS.

The core value proposition is not in API design, it's in the implementation.