This seems incredibly dangerous. Are the speakeasy gyms requiring negative COVID tests? Are they doing temperature screenings upon entry? How diligently are they sanitizing equipment? How well ventilated are these various areas? Why are people ignoring all of these risks, what kind of threat model do they have?
I'd guess the threat model is something like: relatively low local disease prevalence rate, the likelihood that infected people show up to workout is lower than other activities like office-work, and relatively low likelihood of personal adverse outcomes in someone healthy enough to be going to an underground gym. Further, there are major benefits to psychological state, social/emotional state, mental acuity, health,…
Why do randos think they understand the threat model better than the CDC and state medical authorities?