Step 1: From the Main Menu, go to Settings
Step 2: Under Settings, go to iTune Store
Step 3: Click on Location
Step 4: Change your Location to United States as shown
Your iTune Store preference should appear as followed
After the settings has been applied, US ATV available apps will appear on your main menu
If your website icon is still hidden after changing iTune to United States, go to Settings > General > Parental Controls and set the app to "Show"