Hey man thanks for your input!
I have indeed, I always assume they either saw your reply on a post somewhere an decided to add you or are driven by a bot that somehow searches for random names.
About the superstars and sportsmen I don't know, they have plenty of events I wouldn't be surprised if they'd prefer their real family and friends to help them trough those times. I think for them followers and likes are more a popularity contest resulting in more revenue (also would not be surprised if most of their social media platform have a guy behind it that does it for them)
Self promotion without wanting friendship is exactly one of the points I was trying to make and I think it plays very well with the next point you make about split personality. It might indeed already have existed before and that now with social media it is just voiced out more and more apparent and easier to do.
Social media has its benefits indeed, it is a great source for some forms of information. Also yes it is still valuable in staying in contact with friends and family all over the world even with whatsapp and viber etc. Now I can simply post a picture of the holiday I want to share with them in one place instead of having to whatsapp it to each and all. Or if I quickly want to inform the whole lot about something (just examples).
If i want to go into more details with them I would indeed use whatsapp