bug#29568: Bug in find, or my mistake ?

[f0rhum]

Hi
find -version
find (GNU findutils) 4.4.2

I issued this command to remove all files "*_original" from parent tree :
/find .. iname "*_original" -delete/
as you see I forgot the minus sign before /iname/.
The result was all regular files were deleted, just leaving behind empty
directories (I don't really know why dirs remained, maybe because it is
a synchronised folder with some exclusions that prevented remote
deletion and the local were created back).
Is it because /iname/ and /"*_original"/ are both seen as EXPRESSIONS
that always return true so that -delete applies to .. and content as a
whole ?

Thanks
//