You're wrong. There are clear criteria for determining the nature of physical activity (aerobic and anaerobic).
I can give you many examples of heavy physical activity that is not cardio.
yeah, but when talking about heavy physical activity, you're unable to do it for too long. therefore, the rest of your daily activities are cardio. besides the really heavy physical activity which you're only doing a few hours a day, and for most people, only a few hours a week. cardio is short for cardiovascular. When you're walking/fucking/working (physically), and so on, your heart pumps blood faster = cardiovascular activity.
Aerobic exercises are endurance-type exercises that increase a person's heart and breathing rate over a sustained period. Anaerobic exercises involve short, intense bursts of physical activity. Both types of exercise are beneficial for a person's cardiovascular health.