Why are there so many posts that don't interest me on Social Media?

I joined a lot of Social Media sites to sell books. I won’t lie about it. Cheryl Solimini told me it would be a good idea. We met at a book fair and I we talked books and book sales. She had success with social media. 

It became a perk that I was introduced to other authors I liked. New people that I would love to meet someday. Authors that I can commiserate with when I’m stuck. 

I found old friends. I found out what happened to people I used to peripherally know. The early years of social media were good. 

What happened? 

My social media sites are loaded with ads. I’m not talking about someone recommending a good restaurant or movie. We’re talking insurance ads or medicine. Angry people that will create a reason to be angry overtake the happy posts. I’ve seen people who have never posted a postive comment. Why?

People selling me stuff. Angry people. These are taking the fun out of social media. This isn’t the end of social media by any degree, but I wonder if the people I wanted to communicate with have lost their interest in sites. What happened to those friends that used to post? Did they find a new place to talk?