Earlier quoted context omitted.
Well imagine a criminal is holding a piece of your property or even a person and not revealing where that is. Do you think it's reasonable to hold them for 30 days and then let them go and say "ah well I guess you can return that/them if you want cuz you did your time." A charge of contempt is still a charge.
Do you think it's reasonable to imprison someone for life if they don't tell you where they hid your car? And holding a person is already a separate charge - kidnapping and unlawful imprisonment.
An actual sentence eventually has an end.