Q. Why are multiple objects in a view transformed, when I select and transform just a single object?

A. Suppose you have two objects in a viewer. You select one object and rotate it. The other object rotates as well, even though that object is not selected (and neither is Top). Why is that?

The most likely reason is that the transform mode on the selected object is set to "parent". Parent transform mode means that transformations on the object are applied to the object's parent, in this case, the Top object. Transformations on the parent object are applied to all of its child objects. That is why the other object in the view is also transformed.  You change the transform mode in the Object Editor, by changing the Transform Mode.