You may be misinterpreting it. It is more akin to an old stoic saying do not worry about things that are outside of your ability to control.

You can spend every waking hour researching charts, trends, news, and do everything to make educated financial decisions. The lawmakers and corporations will do the same. However shit always happens. Good shit. Bad shit. There is always going to be a level of uncertainty.

So when people say the market will decide. Just know that it is what is going to happen is going to happen. Whether you want it to, or not.