Why did Joseph pick Simeon to be a hostage?

[tonychanyt]

Genesis 42:24

[Joseph] turned away from them and began to weep, but then came back and spoke to them again. He had Simeon taken from them and bound before their eyes.

Cambridge Bible for Schools and Colleges:

Simeon was selected to be retained in prison as the next oldest after Reuben. Reuben may have been spared, either for his previous kindness, or because, as the eldest, he would be responsible for carrying the report to Jacob. That Simeon was also the most cruel is an inference from Genesis 34:25 and Genesis 49:5-7

Similarly, Matthew Poole's Commentary:

He chooseth to punish Simeon, partly, because next to Reuben he was the eldest, and, as it may be probably gathered from his bloody disposition, Genesis 34:25 49:6, the most fierce and forward against Joseph, when Reuben was for milder counsels, as we see here, Genesis 42:22 38:29; and partly, because the detainment of one of so perverse and furious a temper would least afflict his father, and most secure Benjamin, who was to come with his brethren. He

Gill's Exposition of the Entire Bible:

and took from them Simeon, and bound him before their eyes; who perhaps was the most cruel and hardhearted among them; and it appears from the affair of Shechem, that he was a man of a fierce and bloody disposition. According to Jarchi, it was he that said to Levi, on sight of Joseph, behold this dreamer cometh; and that it was he that cast him into the pit; and, as the Targum says, advised to kill him: and perhaps Joseph might pitch upon him as the hostage, not only because he had used him more evilly than the rest, but because he might observe he was less concerned, and not so much humbled now for the evil he had done as the rest were; as also he might choose to detain him, as being not so much in his father's affection, because of the affair of Shechem, and so be a less affliction to him than if it was another; and besides, he might fear that being of a perverse and boisterous disposition, he would vehemently oppose the sending of Benjamin into Egypt, which Joseph was so very desirous of.

Why did Joseph pick Simeon to be a hostage?

The oldest brother wasn't a bad guy. Simeon was the 2nd oldest and the cruelest from Joseph's reckoning. He was the oldest among the conspiratory brothers.