[rchaud]

It's the difference between one-way and two-way methods of communication as well as past events vs live events. TV shows are static, they are completely unchanged by your personal opinion as you watch it. You cannot submit a comment on a TV episode, nor is there any mechanism for the episode to reflect the impact of your comment (likes, replies, etc.)

In fact, even FB/Twitter/IG aren't "real-time". They don't show all the likes as they're coming in. They specifically delay showing the full number so you have a reason to come back and re-check. If you see a higher number of likes, you're going to come back again to re-check.