What is the reason for the difference in the ruling on blood, between the opinion of its purity based on the evidence of the Companions praying with their blood during battles, and the opinion of its impurity with a pardon for a small amount of it, and which of the two opinions is more correct?

Scholars differ concerning the purity of human blood. Some later scholars, like Ibn Uthaymeen, consider it pure, analogizing it to the purity of a human corpse. However, the majority of scholars hold the view that blood is impure, and more than one scholar, including Imam Ahmad, Ibn Hazm, and An-Nawawi, have reported a consensus on this. A small amount of it is excused by most scholars. As for Muslims praying with their wounds, this is attributed to either their inability to remove the impurity or the blood being in small quantity.