I disagree. If I have say 100,000 followers, it doesn't cost me any attention. But if I am following thousands of users, I am going to have many thousands of posts in my feed per day and I would doubt that all of those posts will be interesting for me.
On the other hand, it's all about what's interesting. If you find my posts interesting, you can follow me. If you don't, please don't. I might look at your last couple posts to see whether you post topics I am interested in. This way everyone gets to see the kind of posts they want, which might not be the same as the trending page.
It is my opinion that all of these listed users are not people choosing people to follow but are using this auto-follow bot.
Yes, they are using the auto-follow bot to gain subscribers. They then unfollow people in droves to make their profile seem legit. The next step for them is to run services like resteem.com and resteemexposure.com