Here's Johnny

 

On the eighth day they came to circumcise the child, and they were going to name him after his father Zechariah, 60 but his mother spoke up and said, “No! He is to be called John.”

…

62 Then they made signs to his father, to find out what he would like to name the child. He asked for a writing tablet, and to everyone’s astonishment he wrote, “His name is John.” 64 Immediately his mouth was opened and his tongue set free, and he began to speak, praising God. -- Luke 1

This passage is commonly passed over without comment. I believe it is the only place in the Bible where the custom to name a child after the parent is mentioned. In the long genealogy of Joseph given later in the gospel, there are no twinned names. And the issue seems to be raised here to make God’s position on the matter clear: don’t do it. It goes against the divine will. Here God strikes the father dumb to prevent it. 

Although we readily accept it today, although it is almost a commonplace, it is obviously wrong. It denies the child their individuality. You are declaring them a part of yourself. It shows a terrifying narcissism.

As practical advice, if you know someone of this sort, you are wise to steer clear.

And, if we were truly a society that cared about children, this would not be acceptable in polite company.

We do not. It is precisely in said "polite company" that it is most common.