I fully agree with you dwanthny. This metadata things has also not hindered my reading experience in the slightest.
I just mentioned it here because it creates sort of an inconsistency between the two functions in Modify ePub that might confuse the users as mentioned by Magnus in post #7.
Maybe the Remove function could be changed to remove "unknown" metadata, i.e. metadata that is not dc conforming and not created by calibre.