Because an MDE only protects VBA code. You can also edit Macros in an MDE.
From the Help file:
Saving your database as an MDE file prevents the following actions:
- Viewing, modifying, or creating forms, reports, or modules in Design view.
- Adding, deleting, or changing references to object libraries or databases.
- Changing code using the properties or methods of the Microsoft Access or
VBA Object models -- an MDE file contains no source code.
- Changing your database's VBA project name using the Options dialog box.
- Importing or exporting forms, reports, or modules. However, tables,
queries, and macros can be imported from or exported to non-MDE databases.
Any tables, queries, or macros in an MDE database can be imported into
another database, but no forms, reports, or modules can be imported into
another database.
