This part worries me too..

The Steemit brand and logo are protected by intellectual property laws, including copyright and other proprietary rights of the United States and foreign countries.

Many of them are using Steemit logo for their photos, footer signatures, community development activity etc. A lot usage is from Steemit posts, which in a way is considered commercial(that is why unauthorized copyright photos are discouraged here). I hope Steemit team will come up with more clarity.