Of course the blood of RasulAllah sallAllahu alayhi wasallam is pure. The impure blood is in reference to the rest of people when they perform cupping. Also, cupping is a sunnah in the sense that it has been recommended by the Messenger sallAllahu alayhi wasallam.
what exactly is it that you don't accept? the method of cupping described? or that cupping itself does not mean 'drawing blood by certain methods'? or that RasulAllah SallAllahu alayhi wa sallam did not take out blood?
Sure, I understand your meaning there but the difference is that here we are referring to the sacred blood.
i haven't watched the video, however you would definitely know that fuDlat al-Sharifah of Prophets are tayyib and tahir for the ummah, as for themselves (due to their status, and purity of soul) they are not.
I don't accept that Rasulullah Salla Allahu alayhi wasallam practised cupping the way it was explained or is commonly explained these days. Everything from his (Salla Allahu alayhi wasallam) sacred body was pure and good.