These people call themselves “Sign Followers” and they don’t just hanlde snakes but take Mark 16:17-18 literally and practice handling fire, healing the sick, drinking strychnine, and casting out demons. And appearenlty this is done not to prove anything, but conform to the Word of God. The churches are independent and are connected to three American movements in Protestantism: Holiness, Pentecostalism, and Fundamentalism. These people generally consider themselves as Holiness, and like fundamentalist believe in the literal interpretation of scriputure.
And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues; They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover. - Mark 16:17-18
There actually has been a book written about the Coots family (the pastor who was arrested was actually interviewed for the book). The book is The Serpent Handlers: Three Families and Their Faith written by Fred Brown.
The whole thing sounds to me like Luke 4:12 where testing God is not trusting God.
See article about pastor being busted: