Someone who goes short a stock doesn't own the stock but they do...

Someone who goes short a stock doesn't own the stock but they do have a requirement to put up reserves against the short from their capital. Once those reserves exceed the account value they have to go on margin. So nothing is given for free.

Someone who goes short doesn't take the same risk as someone who goes long. They, in fact, take a far higher risk. Shorting exposes you to unlimited losses far in excess of the original investment.

You wish stocks could not be shorted so things would be like real estate. But I would remind you that in most markets now real estate is so vastly overvalued that no one can afford a home and no business can afford a rent. Instead of an active force to regulate real estate from becoming overvalued, what happens is real estate has long periods of great overvaluation usually followed by a sudden collapse during some economic event like the collapse of 2008 in the US. That event threatened the world economy and only by a pure miracle did the world escape from a 1929 style depression that would have gone on for decades. I don't see that as a better outcome for economic stability. Personally, I wish there were a way to short real estate. It would add far greater long-term stability to the real estate market and price rises would more precisely reflect real economic valuations than speculation.