Why does the Unity Scroll View cannot be scrolled horizontally using the finger instead of using the scroll bar

The scroll view cannot be scrolled horizontally with the finger. That makes it essential to make the horizontal scroll bars appear in the scroll view. But there's no such problem with vertical scrolling. Since I do not want scroll bars to appear in the scroll view, I want some means to scroll the panel horizontally using the finger, without using the horizontal scroll bar. This is what I have used:

scrollPosition = GUI.BeginScrollView(new UnityEngine.Rect(0, 0, 200, Screen.height - 20), scrollPosition, new UnityEngine.Rect(0, 0, 4000, 4000), GUIStyle.none, GUIStyle.none);