if you see chapter 2 verse 65 again it says "Be you monkeys, despised and rejected"
despised is what a person is when he is humiliated. so obviously they were (also) humiliated for breaking the covenant of the Sabbath.
i have the famous tafsir ibn katheer in front of me. this is what it says:
(And ask them (O Muhammad ) about the town that was by the sea; when they transgressed in the matter of the Sabbath (i.e. Saturday): when their fish came to them openly on the Sabbath day, and did not come to them on the day they had no Sabbath. Thus We made a trial of them, for they used to rebel (disobey Allah).
(We said to them: "Be you monkeys, despised and rejected'') means, "Allah changed their bodies into those of monkeys and swines. The young people turned into monkeys while the old people turned into swine.''
(We said to them: "Be you monkeys, despised and rejected''), "These people were turned into howling monkeys with tails, after being men and women.''
Ibn Abi Hatim recorded that Ibn `Abbas said, "Those who violated the sanctity of the Sabbath were turned into monkeys, then they perished without offspring.'' Ad-Dahhak said that Ibn `Abbas said, "Allah turned them into monkeys because of their sins. They only lived on the earth for three days, for no transformed person ever lives more than three days. They did not eat, drink or have offspring. Allah transformed their shapes into monkeys, and He does what He wills, with whom He wills and He changes the shape of whomever He wills.
remember reverend, these were times when people had the ability to turn staffs into snakes. obviously the Creator of this ability Himself would have far greater conversion abilities. it was very easy for Him to turn these transgressors into monkeys.