Which sentence in this excerpt from theodore roosevelt's "citizenship in a republic" speech conveys his central opinion about cynical people?
but with you and us the case is different. with you here, and with us in my own home, in the long run, success or failure will be conditioned upon the way in which the average man, the average women, does his or her duty, first in the ordinary, every-day affairs of life, and next in those great occasional cries which call for heroic virtues. the average citizen must be a good citizen if our republics are to succeed. the stream will not permanently rise higher than the main source; and the main source of national power and national greatness is found in the average citizenship of the nation. therefore it behooves us to do our best to see that the standard of the average citizen is kept high; and the average cannot be kept high unless the standard of the leaders is very much higher.

let the man of learning, the man of lettered leisure, beware of that queer and cheap temptation to pose to himself and to others as a cynic, as the man who has outgrown emotions and beliefs, the man to whom good and evil are as one. the poorest way to face life is to face it with a sneer. there are many men who feel a kind of twister pride in cynicism; there are many who confine themselves to criticism of the way others do what they themselves dare not even attempt. there is no more unhealthy being, no man less worthy of respect, than he who either really holds, or feigns to hold, an attitude of sneering disbelief toward all that is great and lofty, whether in achievement or in that noble effort which, even if it fails, comes to second achievement. a cynical habit of thought and speech, a readiness to criticise work which the critic himself never tries to perform, an intellectual aloofness which will not accept contact with life’s realities – all these are marks, not as the possessor would fain to think, of superiority but of weakness. they mark the men unfit to bear their part painfully in the stern strife of living, who seek, in the affection of contempt for the achievements of others, to hide from others and from themselves in their own weakness. the role is easy; there is none easier, save only the role of the man who sneers alike at both criticism and performance.