Despite frequent efforts to combat racism, almost no research has explored how to cultivate positive experiences of thriving Black culture on Reddit. In this case study, we surveyed users of r/BlackPeopleTwitter (BPT)--a large, popular subreddit that showcases screenshots of hilarious or insightful social media posts made by Black people (mainly from Black Twitter). Our research questions seek to understand users' motivations for visiting BPT, how they experience a sense of virtual community (SOVC) and membership in BPT, and how BPT's governance influences these experiences. We find that that users come to BPT primarily for excellent humor and entertainment, sociopolitical context on issues relevant to Black people, and/or partaking in the shared Black experience. Black users are more likely to report higher SOVC and to identify as members, whereas non-Black users are more likely to identify as guests or visitors to the community. To protect Black expression, the BPT moderation team implemented a governance strategy for verifying racial identity and limiting participation to only verified users in certain threads. Our data suggest that this policy is a contentious but influential aspect of SOVC that simultaneously constructs and challenges the sense of the subreddit existing as a safe space for Black people. We synthesize these results by discussing how: differing platform affordances across Twitter and Reddit combine to cultivate a thriving Black community on Reddit; the need for Black authenticity on an otherwise anonymous platform can guide future research in identity verification; and the limitations of this study motivate future work to support all marginalized communities online.