The answer to 'why is my dehumidifier blowing hot air' is that it is normal and expected behavior for a dehumidifier. Dehumidifiers work by drawing in warm, humid air from the room, cooling it to remove moisture, and then blowing out the now warmer, drier air. This hot air exhaust is a natural byproduct of the dehumidification process.
The compressor and refrigerant coils inside the dehumidifier absorb heat from the air as moisture is removed. This heat is then released into the air that is blown back into the room, causing it to feel warm or hot. This is a sign that the dehumidifier is working properly to reduce the humidity in your home.