Responding to terrible things
In response, our Lord simply goes about the business of the Kingdom of God: teaching, proclaiming, and curing.
There are other times in the Gospels when our Lord responds immediately this same accusation (and others), but in this case, he chooses simply to continue God’s work.
In our own lives, when we hear terrible things being said about us, about our faith, etc. we would always do well to exercise discernment – seeking the grace and the wisdom of God – so that we may rightly respond and remain faithful in that time and place to the work and the message given to us.