If a child is conceived via surrogate and raised by inverts and the law does not provide for his inheritance, why should that child be punished for doing absolutely nothing wrong?
This is what is meant by "the weakest" - children who are being put in terrible situations by immoral people should be protected.
Ignoring the problem will not make it just go away.
Remember also that this prelate is in an advisory role - his statements are not "doctrine" and are attempts to deal with larger moral issues.
Why be reasonable and tell the truth when you can just bash the Catholic Church?