Hi and welcome to the QlikCommunity,
What happens to you is what is expected to happen, how else could you reload all information without seeing it? What you can do, however, is to avoid users to reload the document, logging in the document as ADMIN, the to the Settings menu, Document Properties, Security tab and unchecking "Reload" from the user privileges list.
So in your case, when USER1 and USER2 log in, will see all their respective information, but they will not be able to reload and therefore not be able to see any non corresponding information.
Hope that helps.