Sectarianism, no true scotsman fallacy... Equating bigotry and intolerence with his particular brand of religion, termed "Christianity", when in reality, many Christians do not support a return to the middle ages.
The ignorance extends to false generalizations about drugs, where #dunning-kruger may fit...
About funerary rites and disposal methods, no matter if his claim is true or not, I think that to many people any novel idea, or even the practices of other cultures may appear to be distasteful. Think of sky burial, for instance. Even cremation is avoided by some who insist on ground burial and there are poetic descriptions about how old life spreads feeding new life. And it's always sensitive because it relates to human death and the fears surrounding it, a main reason of religion. For biological adaptation reasons, it's also normal to feel repulsion when thinking about cadavers. It's probably considered a good topic for propagandists like Kincaid to play with, for those reasons.
When communion with Christ through the body and blood
Yes, that's disgusting, too, so are relics. Unless perhaps you were indoctrinated in the strange idea. And here too, some people have pushed it as far as cannibalism or actual blood drinking... I know of a Gnostic cult leader who claimed that Jesus actually used bloodletting and that his disciples actually drank some blood. Then we shouldn't forget that theocratic Satanists wouldn't exist without the Christian tradition and its rites, that they reverse or parody.
Finally, humans have died since they existed and so did their predecessors, Christianity is a fairly new religion.