Extract unlocks PDF - How can I secure without a password?

I lock the final PDF that I create using File>Save as Other>Reader Extended PDF>Enable more tools.

I thought this was a secure way to lock my forms from being edited. However, I just realized today that when a page is extracted it can then be edited. Words can be added, it even has all the fields with custom JavaScript that can now be edited.

I am very disappointed to find this. How can I lock a form without a password and have the file secure?

Thank you for any suggestions.

I use Adobe Acrobat 2017