It sounds normal to me! My cats follow me from room to room. I always shut the bathroom door, so when I come out, they're sitting outside waiting for me. If they can't find me, they'll start meowing and won't stop until I come out and give them attention. I don't think there's any fascination with the bathroom per se, so much as a fascination with places they can't access.
I wonder, are your cats older? I've noticed that younger (less than 3 years or so) cats seem more independent. My thirteen-year-old and eleven-year-old have gotten more clingy over the years. They'll leave me to sleep in another room only if they know where I am, and they come out to check on me periodically.
