I haven't noticed this, but I did wonder how some might feel after I unfollowed them. When I first joined, I thought it was only polite to follow whomever followed me, now I know better.
So, in case someone wonders why they might get unfollowed, it's because I was tired of seeing stuff on my wall that didn't interest me. It's not personal, often it's just that the people YOU follow are not into what I'm into & I don't want to see a bunch of comments about lingerie if I don't wear it, (just an example).