No, mold is simply one of the tools mother nature uses to decompose organic substrates. Mold growing inside a confined space, where we breath in the concentrated spores, is very potentially harmful. Absolutely mold growing in your home is not healthy.
Put a heater under your plants?
Poly tent covers help to hold in the heat early in the season when the bales are “conditioning” they give off tons of heat like a natural furnace underneath. It is the bacteria that are doing the decomposition that create the heat as a naturally occurring phenomenon of the process. People often see a freshly stirred up compost pile will steam for a couple of days when new organic matter is added, this is another example of the heat generated by the actively consuming bacteria munching away on the freshly introduced organic matter.