Because Flock is the first company to so brazenly violate the post-2011 social contract: if you're going to track somebody you need to give them coupons and content as compensation. They have failed to provide the people whose privacy they are violating with internet drama and buttcheeks videos. Other companies with many times greater reach and market cap collect GPS, cell tower, and 802.11 ESSID data to observe their users' movements; they track them across web sites and apps without explicit consent to serve personalized advertisements and adjust prices for durable goods and services depending upon user behavior. They do this with impunity because people enjoy short-form videos and image macros and will readily trade their privacy for easy access to them. Flock has nothing to offer in this regard. This is why they are shunned whereas other companies that understand how this game is played are forgiven for equivalent or worse sins.