Do you have to like pain to be a rope bunny?

No. Plenty of people who love being tied have no interest in pain at all, and a lot of rope is comfortable by design.

What rope reliably produces is pressure, stillness and restriction. Some people find a hard position genuinely painful and that is part of the appeal for them; others want the floor work, the closeness and the quiet, and would stop immediately if it hurt.

It matters at negotiation. Saying "I'm a rope bunny" to someone who assumes that means you want a challenging suspension is how people end up in positions they didn't ask for.