After some research it seems that there is no way to find an inactive gameobject by tag.
solutions exist however to access inactive gameobjects:
1 - Store inactive game objects in an array if you need to reactivate them afterwards (only applies to game objects inactivated at runtime).
2 - Do not deactivate game object, simply deactivate the components you want inactive. If you wish to make the object disappear, deactivate the renderer. If it is a specific script, deactivate that script, etc.
This solution will allow you to still find a game object by its tag name.
