IMHO there is a difference between an activity that raises your heart rate, and movement. www.livestrong.com/article/114986-definiti
Activity is a good thing! But if you aren't pushing yourself and raising your heart rate, you really shouldn't call if "cardio". www.ncbi.nlm.nih.gov/pubmed/12468415
But again, IMHO, too many people spend too much time doing hours of cardio. Balance is needed and strength training should NOT be left out of one's exercise routine.
...and by the way, I do walk & time myself and have a goal to meet or exceed a certain # of minutes per mile. (I am physically unable to run.) I also include hills and occasionally, nordic walking poles.