This is one of those 'grey areas' that gets a flip-flop every now and again, but has been this way for a number of years now, since a user complained that deleting the bios data in MC should not result in that tag being removed from the file also as that meant that the data was lost.
At that time, this was considered incorrect and so, we have what we have today, and it's not considered to be broken. It's one of those that that really depend on your angle of approach...
-marko.