It literally is not zero sum though? AN ASPECT of options trading can be zero sum. The premium I charge you for an option is a zero sum. I get that and you lose it. If I don’t cover then you could also potentially consider that part of it zero sum. If I do cover it is not zero sum. Also, even if I didn’t cover, if you exercised the option then when the stocks change hands there is a zero sum transaction.

If the stock market was zero sum then the stock market would never go up or down. Companies enter and exit, mergers happen, etc there are so many aspects of the stock market that make it not zero sum.