Jesus Christ very seldom took any notice of the mists of calumny that drifted round Him. ‘When He was reviled He reviled not again.’ If ever He did allude to them it was for the sake of the people who were harming themselves by uttering them.
So here, without the slightest trace of irritation, He quotes a malignant charge which was evidently in the popular mouth, and of which we should never have known if He had not repeated it; not with anger, but simply in order that He might point to the capricious inconsistency of finding fault with John and Himself on precisely opposite grounds.
The former did not suit because he came neither eating nor drinking. Well, if His asceticism did not please, surely the geniality of a Christ who comes doing both will be hailed. But He is rejected like the other.
What is the cause of this dislike that can look two different ways at once? Not the traits that it alleges, but something far deeper, a dislike to the heavenly wisdom of which John and Jesus were messengers. The children of wisdom would see that there was right in both courses; the children of folly would condemn them both. If the message is unwelcome, nothing that the messenger can say or do will be right.
The same kind of thing is common today. Never mind consistency, find fault with Christianity on all its sides, and with all its preachers, though you have to contradict yourself in doing so. Object to this man that he is too learned and doctrinal; to that one that he is too illiterate, and gives no food for thought; to this one that he is always thundering condemnation; to that one that he is always running over with love; to this one that he is perpetually harping upon duties; to that other one that he is up in the clouds, and forgets the tasks of daily life; to this one that he is sensational; to that one that he is dull; and so on, and so on. The generation that liked neither piping nor mourning has its representatives still.
[Excerpt from MacLaren's Expositions]