In my opinion, "Parasite" is an extremely dumb name to choose for something that is shown as an error message to a casual user. It only raises questions, and not everyone out there go to this thread to read about it.
I think "Corrupt metadata" would be better. Less info for the programmer, yes, but at least the non-programmer user wouldn't get a heart attack reading about parasites on their computer. And the programmers should have a logging system in place so it was possible to run GIMP in verbose logging (debug) mode to find out more. Mrs. Johnson, 65, wouldn't get a heart attack, she would be sad for a moment when her files are lost, and the more technically savvy high school kid could find out more by using the verbose logging mode, and everyone is happy in the world of GIMP.