Why do some prolifers think this is a good rebuttal to organ donation analogies?

This rebuttal to organ donation analogies seems to have gained popularity:

"In order for a bodily rights argument to be analogous to abortion, the hypothetical needs to include the following five elements:

• If you refuse bodily donation, someone else will die.
• You chose to risk making this person’s life depend on you.
• No one else can save this person.
• Your bodily donation is temporary.
• Your refusal means actively killing this person, not just neglecting to save him."

Apparently the original source of the argument is here.

The problem is, I just don't understand why they would even consider these factors relevant. Even if all these factors were present in an organ donation case, bodily autonomy would still come first. Is there some sort of cultural context I'm missing? I might go and ask them on the debate subreddit, but if I'm missing something obvious I'd rather find out here first.