>But it is obviously bullshit, as the real companies behind some stocks have a real value. Like for example they might own a building that is worth one billion dollars (simple example). If you take away all the stock market shenanigans, you still own part of that building via your stocks.

But as a stock holder even of a public company, your shares can get diluted to smithereens when they issue new shares to raise money.

For a laugh check out the chart of Helios and Matheson, the MoviePass company that had a fly by night stock spotlight experience a couple of years ago. It's so diluted, the historical price looks like the stock was worth bazillions in the past chart numbers.