One nuance of platform design is recognizing that the same user may play a different role in differing interactions. The same person may be both a host and a guest on Airbnb, although he or she will typically perform only one of those roles in a particular interaction. On YouTube, users may upload videos as well as view them. A well-designed platform makes it easy for users to move from role to role.
It's likely in most cases that UGC contributors are also consumers. With BPMs it's likely a little different. As a "company" they are likely to both publish and consume content, but it's likely different people, working on different teams within the organization who do one vs the other.
