Because most of them were arrested for committing crimes of some sort, unlike the hostages who were just quietly at home?
I definitely think people should go through due process and be treated decently while in custody and Israel has to answer in that regard but let's not pretend that the two situations are exactly comparable.
Today I saw somebody talking about a 13 year old "held hostage" by Israel and it turned out to be someone who'd gone to jail for stabbing a woman as she walked her kids to school.
And according to Al Jazeera, hardly pro Israeli, it's nowhere near 10,000. The article is dated 8 October.