The answer to 'why is my steam cleaner pet stains' is that pet stains can be difficult to remove with a standard steam cleaner. Pet urine, feces, and other organic matter can penetrate deep into carpets and upholstery, making them challenging to fully extract with a home steam cleaning machine. The heat and moisture from a steam cleaner may spread the stain further or set it more deeply into the fibers.
To effectively clean pet stains, you may need to use specialized enzymatic cleaners or professional-grade extraction equipment. These are designed to break down the organic compounds in pet accidents and lift them out of the material. Attempting to clean heavy or set-in pet stains with a home steam cleaner alone may not be sufficient.