Sentence:  You treat his opinions (though he never thrusts them on you) about "the Church," and his duty, and the souls of his parishioners, with civil indifference, as much ado about nothing; and his rubrical eccentricities as <WSD>puerilities</WSD>. 
Meaning of the word marked with <WSD> tags:  That which is puerile or childish; especially, an expression which is insipid or silly.