Is rope bondage supposed to hurt?

Not inherently. A lot of rope is comfortable, and a lot of rope work is closer to a craft project than anything painful.

Some positions do hurt, and some people want that. Predicament ties and hard suspensions are deliberately demanding. But a rigger who causes pain they didn't negotiate isn't being a sadist, they're being careless.

The pain worth taking seriously in rope isn't the interesting kind. Numbness, tingling and cold in the hands are nerve compression, and that is a stop-immediately signal, not something to push through.