Human flesh is "unclean" not Kosher , not Hallal in most religions , but is the first choice for transplants, is transplanting fundamentally different from consumption?
Taboos have some strength, but the cheapest and best way to stay alive tends to be a strong argument.
There is a scientific reason to worry, there are a lot of diseases that do not plague human beings but do affect other animals , there are also some that prefer one or the other and are more of a problem for one than the other.
Might a chimera hand the keys to humanity to a new pathogen?