1. It’s not clear who wrote the note, and they didn’t leave contact info or any opening to a negotiation. If the note had said “this AC must stay on at all times, please call 111-222-3333 with any questions - building engineer” that would’ve completely reversed the morality of story for me. But the note asserts authority by making this non-negotiable demand (which is the part that seems patronizing to me—I agree with TFA here) and doesn’t justify that authority at all, no “I’m the owner” or anything.
2. The first step of finding a compromise is knowing what everybody wants. The author of TFA didn’t seem to do that in the story, and his apparent lack of curiosity about the compressor does not reflect well, I agree, but neither does a threat from whoever wrote the note.
My wild guess here is that the person who wrote the note worked in maintenance and was unhappy about the building warming and cooling and wanted a stable temperature. The resolution may well be that the author has to find a new place to do yoga, but if he’s not interested in air-conditioned yoga, and the building’s authorities aren’t interested in tenants who want the AC off, that outcome might have been inevitable anyway.