"The Island of Trid" joke

Once upon a time, in the middle of the ocean, there was the Island of Trid.
It seems that most of the Island of Trid was covered by a large mountain. On this mountain lived a Giant. The Giant did not allow Trids on his mountain. If a Trid dared to climb onto the mountain, the Giant would kick him into the ocean. Trids are notoriously bad swimmers, and frequently drowned when kicked into the ocean.
The Trids were a very sexual people, and the population had grown quite large. Every square inch of the island, except the mountain, was crowded with Trids.
The Trids spent their days crowded together, dreaming of the open space available on the ever visible mountain. Every few days, a Trid would decide he couldn't stand the crowds any more. He would start to climb the mountain, and the Giant would kick the Trid into the ocean.
The Trids were a very depressed people.
One day a traveling Rabbi visited the Island of Trid. Despite their overcrowded conditions, the Trids were extremely generous to this man of God.
The Rabbi decided to return the favor, and to go plead the Trid's case to the Giant. "Surely the Giant can be convinced to share some of the mountain with you," the Rabbi explained.
The Trids were horrified. "Please don't go, Rabbi", the Trids implored. "The Giant will kick you into the ocean, and you will surely drown."
The Rabbi was stubborn, and insisted that he talk to the Giant. The Trids sent out every boat they had. They formed a ring around the island, so that they would be able to rescue the Rabbi.
The Rabbi started walking towards the mountain. No sign of the Giant.
He walked through the foothills, and there was no sign of the Giant.
He started up the slopes of the mountain, further than any Trid had ever been. Still no sign of the Giant.
Finally he reached the summit of the mountain. There the Giant was waiting for him. The Rabbi asked "Tell me Giant, why have you allowed me to climb to the top of the mountain, without kicking me off the moment I started climbing?"
And the Giant replied, "Silly Rabbi, kicks are for Trids!"