All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
That Hadeeth was reported by Al-Bukhari, Muslim, Al-Bayhaqi in his Sunan, and Ash-Shaashi in his Musnad. Those books have nothing of what is mentioned in the question that the Prophet, sallallaahu ‘alayhi wa sallam, could not come out of it due to the heavy weight of what they have thrown on him. Rather, the narration indicates the contrary of what is stated in the question regarding the weight of that intestine of camel. It was stated in the Hadeeth reported by Al-Bukhari and others the following wording: “They brought (some) of its intestines and threw it on his back,” meaning only part and not all of it. This indicates that the mentioned argument has no basis at all.
Attention also should be paid to the danger of listening to the malicious arguments of those who spread rumors, especially for those who have no deep knowledge to be able to refute those arguments or strong faith that can keep one firm against them and be safe from them and from having doubts about his religion. Allaah The Almighty says (what means): {And indeed do the devils inspire their allies [among men] to dispute with you. And if you were to obey them, indeed, you would be associators [of others with Him].} [Quran 6: 121]
Allaah Knows best.