“Last month’s release of Counter-Strike 2 forced a 26GB update for everyone with CS:GO, including Mac users, but after installation those on macOS soon discovered that the update makes the original game as well as the update unplayable because of the lack of support and no rollback option.”
Valve pushed a 26GB update to Mac players, broke the game they had, and only then posted an FAQ saying macOS is done. Mac, DirectX 9 and 32-bit users together made up under one percent of CS:GO players. Refunds cover only the Prime upgrade and end December 1. Apple still has no native Vulkan, and its users pay for that with their game libraries.