User blog comment:Fliu/My Thoughts on the Dressrosa Arc part 2/@comment-5780397-20150616165252

First, it is necessary to specify one thing: Law and Sanji were not hit with Parasite, they were merely immobilized with strings. Doflamingo had restrained them, but could not control their movements. Proof of it is the fact that as soon as they were cut free, they regained their freedom immediately.

As for Parasite, we have seen it in a flashback: Doflamingo needs to attach the string to the opponent's nape for the ability to work. Most of the opponents he has used it on were showing him their back (aside from Rebecca, but he might have just caused a string to rain down from the Birdcage, as he did when he set it up: Rebecca's guard was low at the time, and her battle skills cannot hold a candle to Doflamingo's). Rufy is much stronger, faster, and more skilled than Rebecca, he would not leave Doflamingo the time to do it, or show him his back while remaining an easy target. Besides, Doflamingo clearly wanted to pummel Luffy with his own hands, and in the heat of battle, one cannot always make the right moves, especially when you are enraged and having a hard time.