However, you only need the password if you want to be root, and most of the stuff malware wants to do (including keylogging, which the article mentions; requiring root to intercept keyboards is only moderately useful if the regular user can gdb -p whatever app has the password field) does not require being root.
Oh, is this new in Lion or something? I've never seen that prompt before. (But in any case, there are other options such as clever use of DYLD_INSERT_LIBRARIES.)