They're using the definition of "ridesharing" that everyone used before Uber came along. Uber branded itself a "ridesharing" app in order to avoid regulations on taxicabs, despite the fact that what Uber does has nothing to do with ridesharing.

To differentiate the things like car pooling from things like Uber.

I think probably because "ridesharing" is a pleasant word that evokes a nice image of people carpooling together instead of conjuring up exploitative, shit companies like Uber