Anything becomes halal if it can save ones life in a death/life situation.
Regarding the pain:
The swift cutting of vessels of the neck disconnects the flow of blood to the nerve of the brain responsible for pain. Thus the animal does not feel pain. While dying, the animal struggles, writhes, shakes and kicks, not due to pain, but due to the contraction and relaxation of the muscles deficient in blood and due to the flow of blood out of the body.
Campaign against Halal:
It is perfectly alright for non-muslim to protest against issuing halal certificate in an ethical manner without spreading hatred. Challenging the legal system would have been ideal than what happens today. It is not common Muslim who asks for Halal certificate but big businesses. Whether its run by Muslim or a non-muslim. So, who ever wants to stop the Halal certification, tell that to these businesses.
Bottom line: Today, They are using the halal issue to hurt the Muslims economically.
Tomorrow, a group will make the beard as an excuse to loot the Muslim's property and take advantage of the situation.