Many girls ARE in effect “hostage” when they are waiting a long time for a response from the boy’s side. I know so many girls who strongly (and in my opinion wrongly) hold that it is wrong to make a date with someone who is ready to say yes, if the girl is still waiting to hear from someone else who was suggested before this, but who just did not get back to the shadchan yet (maybe because he has “lists” of girls)
If that would be the norm, that would indeed validate the notion that the boys are holding them “hostage.”
Since that is not the norm, you can’t really consider it anything, since the girls who do that are being dumb.
If the girls intend to wait for an answer before moving on, they should simply make that clear to the boy. It is a simple solution.
I know myself, if a shadchan had called me and said here is an idea, and the girl is not moving on until she gets an answer, I would have responded immediately: “Tell the girl the answer is no, and she should move on.” And then, if I decided to date her, I would call back and say “I want to date her, does she want to date me?”
Simply: You can’t do stupid things without telling me and then blame me for not figuring you out. Unless I am your husband, which is exactly the point.