One does not invest in markets. One invests in assets, preferably productive assets.
If I drink milk, I can either continue to buy it at the store, or buy a cow. By investing in a milk-producing asset, I've made myself market neutral to milk prices. I'm pretty sure that a single cow would actually be more milk than I would consume, so I run into the inconvenience of the asset not trading in odd lots.
Housing has the nice feature that it can be conveniently bought and sold in units that match my consumption (unlike half-cows). I think the analogy of being short housing is apt as well, because housing is something I am pretty much certain to consume.
If I drink milk, I can either continue to buy it at the store, or buy a cow. By investing in a milk-producing asset, I've made myself market neutral to milk prices. I'm pretty sure that a single cow would actually be more milk than I would consume, so I run into the inconvenience of the asset not trading in odd lots.
Housing has the nice feature that it can be conveniently bought and sold in units that match my consumption (unlike half-cows). I think the analogy of being short housing is apt as well, because housing is something I am pretty much certain to consume.