Simplify the following text for a Grade 11 native English-speaking person.
Original: The Borkum and Helgoland camps were called `` volunteer '' ( Hilfswillige ) labor camps and the labourers in those camps were treated harshly but marginally better than the inmates at the Sylt and Norderney camps .
Simplified: The Borkum and Helgoland camps were `` volunteer '' ( Hilfswillige ) labor camps and the labourers in those camps were treated harshly but marginally better than the inmates at the Sylt and Norderney camps .