Fundamental
The fundamental point is that (whether you like these or not*) drive letters are fundamental to Microsoft OSs.
And that makes writing a version that forgets that some drive letters are going to be for external or removable drives fundamentally stupid.
Particularly since an external USB connected HDD is the basis of many a SOHO backup system. Windows already handles that pretty poorly - every time I swap my backup HDD over I find that it has assigned a new drive letter, which I have to then reassign, because my b/u software is going to be writing to H:\folder
And every single f***ing time I have to spend a couple of minutes remembering how (where) to do that because it's almost, but not quite obvious.
*I do, for brevity. Saying "Drive H" is so simple compared to a path name.