The Mach kernel started as a derivative of a BSD kernel. Years later the XNU kernel was created by combining the Mach kernel with code from newer BSDs, therefore it’s totally fair to describe macOS as a BSD. From my very limited exposure to BSD conferences, using Macs is pretty common there as many developers see their community-developed BSDs more for headless use they SSH onto.
The Mach kernel started as a derivative of a BSD kernel. Years later the XNU kernel was created by combining the Mach kernel with code from newer BSDs, therefore it’s totally fair to describe macOS as a BSD. From my very limited exposure to BSD conferences, using Macs is pretty common there as many developers see their community-developed BSDs more for headless use they SSH onto.