To break down that position, explain it like this:
In order to to stimulate production through consumption, you must create false demand. This false demand misallocates resources because nobody is smart enough to figure out the best thing which should be subsidized. This creates bubbles which eventually pop, leaving people out of work. In addition, the excess resources which were used during the inflation of the bubble are wasted.
It's not possible to be an omnipotent, infallible economic planner. If instead you allow production to naturally follow the availability (or scarcity) of resources, we will get much closer to optimal production in relation to the real demand. The reason for this is mainly because entrepreneurs must maintain a profit margin. In order to do so, each company has to weigh demand, costs, labor, and production capacity, and do this weighing constantly.
The free market is a natural, organic delegation of what we all want: a vibrant, mostly stable, productive economy where everyone's standard of living rises with each new innovation and each increase in efficiency.