We are conditioned to seek meaning in life. Having meaning equates to setting goals, and achieving goals means to be successful. Success leads to wealth and, apparently, happiness.
It all comes down to wealth, in other words economic activity. Economic activity and the acquisition of 'stuff', or 'experiences'. Or following the usual path through life, a path that is predictable and easily controlled.
Always busy doing something, aiming for some goal. Must keep at it, the great distraction. Busy-ness means no time for free thinking; while the chasing of success also means running from the fear of losing.
Being without purpose gets you out of the game, but it goes against the grain of everything you are brought up to believe. The horror of having no meaning to life, no goals, no future, no get out of whatever you think you are in.
But the experience is the meaning. You can still go places, just don't be fixated on the outcome. It's OK to own stuff, just don't overdo it or become attached to it. And stop when there is enough.
If you need to tack starboard, don't go port, just follow the natural rhythm of the wind.
Life without purpose does not mean chaos, it does not mean throwing the dice and hoping for the best or being cajoled into a route you don't like. It is experience, acceptance, doing what feels right, all while not being fixated on some predetermined future state.
Society wants your life to be a to-do list, with each item already written down for you to check off. Being without purpose lets you tear up the list and operate on your own terms, in tune with the cosmic whatever-it-is.