So it makes sense that there is an ideal physical form of a man, which is definite (quantifiable) and unchanging (i.e. no evolution). I have never heard of Quetelet, but I doubt he did anything more than put a series of numbers to this preëxisting notion.
You implicitly suggest this comes from Christian doctrine (?) which is strange as it's recorded in the New Testament (https://www.biblegateway.com/passage/?search=john+9&version=...) that Jesus was asked who had sinned in order that a blind person had become blind and he responded that no-one had, that it wasn't the result of sin.
Now, scholars who wanted to control the people's behaviour might find it beneficial to promulgate a position that sin caused deformity but it seems quite at odds with this NT account of the position of Jesus on the matter. Moreover the greater message from Jesus is to bring succour to those who are weaker, and that we are all sinners deserving of God's wrath.
I don't doubt that your suggestion matches the position of some Christians, but that does not make it a Christian position - it seems more derived from societal superstition than from Christian theology.
That one is obvious.
But you have less obvious non-representative means: average # of sex partners (Pareto distribution), average life expectancy (bathtub curve), average autism-spectrum quotient (camel curve). In all these cases the averages obscure, rather that elucidate.
I wonder what would have happened had he used a statistical mode instead of the mean. He was coming at the problem from the experience of correcting error in astronomical measurement, but it seems like there were some mental gymnastics required to equate individual measures of humans as errors.