I don't think they were declaring war with that statement. I think they truly hoped that they could have a non-violent revolution. I do believe they had the courage and resolve to follow through with whatever Georgie decided, but I don't think their intial thought was, "Hey let's declare war!"
George's response made war inevitable, but as an aside (and perhaps semi-anti-american) The whole point of not wanting to pay taxes seems now a little snotty considering Britain incurred those debts protecting the Colonies from the French and indians!