Finger In Tashahud And Tawatur
The index finger of the worshiper’s right hand is raised to emphasize God’s uniqueness during Tashahhud. Reference: http://www.oxfordislamicstudies.com/article/opr/t125/e2348 Significance and concept of Tashahhud: https://en.wikipedia.org/wiki/Tashahhud
The opinion of religious scholars can also be far fetched. Simply raising a finger a tiny bit and moving it does not count as affirming the oneness of good. That sounds frankly silly
Many sects move the finger all throughout the tashahud when things completely unrelated to the oneness of God are being talked about. That is the point