This script quickly deletes the selected area on all layers in an image. You can download the script here: FP's Delete Selection All Layers Script
The preview image was created by selecting the text, inverting the selection, and then running the script.
Download the zip file, open the zip file by double-clicking on it and copy/paste the script to your GIMP scripts folder (ie...C:\Program Files\GIMP-2.0\share\gimp\2.0\scripts). Refresh your scripts and you're ready to go. The script can be located under the Select > Delete Selection All Layers
Let me know if you have any trouble or need additional information.