I wonder if they just let super polluting gas free

Almost certainly. Although at least they all use the newer R32 coolant these days. A typical AC unit uses 0.5 to 1kg of R32 coolant, and releasing 1kg is about the same as 1 person taking a 1000km flight (from a quick search). If you replace the coolant every two years it'll pollute much more from the electricity used than the coolant being released.