A ridiculous assessment of the passage.
Jesus is rejoicing in the REVEALING......not the hiding. Obviously.
Scripture interprets Scripture and what Jesus said about parables reveals that these simple picture stories were given as judgement to prove the judicial blindness and hardness of heart of those who heard them in fulfilment of Isaiah's prophecy and Christ rejoiced in the goodness of this judgement in Luke 10:21.
Mat 13:10 And the disciples came and said to Him, "Why do You speak to them in parables?"
Mat 13:11 He answered and said to them, "
Because it has been given to you to know the mysteries of the kingdom of heaven, but to them it has not been given.
Mat 13:12 For whoever has, to him more will be given, and he will have abundance; but whoever does not have, even what he has will be taken away from him.
Mat 13:13 Therefore I speak to them in parables, because seeing they do not see, and hearing they do not hear, nor do they understand.
Mat 13:14 And in them the prophecy of Isaiah is fulfilled, which says: 'HEARING YOU WILL HEAR AND SHALL NOT UNDERSTAND, AND SEEING YOU WILL SEE AND NOT PERCEIVE;
Mat 13:15 FOR THE HEARTS OF THIS PEOPLE HAVE GROWN DULL. THEIR EARS ARE HARD OF HEARING, AND THEIR EYES THEY HAVE CLOSED, LEST THEY SHOULD SEE WITH THEIR EYES AND HEAR WITH THEIR EARS, LEST THEY SHOULD UNDERSTAND WITH THEIR HEARTS AND TURN, SO THAT I SHOULD HEAL THEM.'
Mat 13:16 But blessed are your eyes for they see, and your ears for they hear;