Your second paragraph ignores the inference required to go from victim's blood on defendant's shoe to defendant's shoe was in physical proximity to victim's bod

Your second paragraph ignores the inference required to go from victim's blood on defendant's shoe to defendant's shoe was in physical proximity to victim's body. It also ignores the inference required to go from blood is measured as matching victim's to blood came from victim's body. It also ignores the inference required to go from blood was deposited onto defendant's shoe directly by victim's body to defendant was wearing shoe at time of blood deposit and thus in presence of victim's still-bleeding corpse. The (admittedly pedantic) point being made is that proving 'x' never directly supports anything other than the truth of 'x'. Moving from 'x' is true to 'y' is true always requires further inference.