Mountain Bike and Trail Running should be Activities
Yoga is an activity but Mountain Biking is not. This alone tells you how much Strava cares about MTB. No disrespect to yoga but the features of Strava were designed around movement and MTB and Road Riding are as different as any other activities in the activity list.
Come on. You differenciate between Run/Walk/Hike, Canoe/Kayak/Rowing, Alpine Ski/Backcountry Ski/Nordic Ski/Roller Ski. If you were forward thinking enough to create all these separate categories that amount to the same activity then where is Mountain Biking??? For that matter where is Trail running? Another activity that is vastly different from it's road cousin.