Protecting VBA code even if copied into new workbook

I have a situation that may actually be a flaw in Excel.  I have a workbook where I have some VBA code.  I have password protected the code. In the same workbook I have code on the individual sheet by right clicking on the tab and select view code where I enter the code.  When I password protect the workbook code by going into tools menu and selecting VBAproject properties clicking on the protection tab and entering a password.  This will also protect the code I entered on the view code tab of the worksheet as well.

The codes stays protected in the workbook.  However if someones copies the sheet we have had the code into a new workbook the password protection is gone and they can now view the code. 

On this same sheet I have password protected certain cells and when they copy the same sheet the password protection stays for the locked cells but not the code when copied into a new workbook.  Lastly the code that I had protected no longer works when also copied into a new workbook.

I have the following code on the this workbook and when they copy the sheet into a new workbook the code no longer works as well as the passwords.  

Private Sub Workbook_Open()
Dim sh As Worksheet
For Each sh In ThisWorkbook.Worksheets
' Add condition for specifying sheet names if needed
If Date > #1/1/2020# Then
sh.EnableCalculation = False
End If
Next
End Sub

How can I keep the password protection even if someone copies the sheet into a new workbook and also make sure the code still applies when copied into a new workbook.