That's a very spicy argument befitting an atheist. It's kind of demanding the question of shouldn't we then forbid children from participating in any religious activity until the age of 18. After all, children are still forming. An adult can be a Christian.
That is a separate argument entirely which I would happily explore elsewhere.
The current social climate is that, with exceptions like North Korea aside, we accept parents imparting or imposing religious doctrines and practices onto their children.
These practices, however hard they might be to shirk in later life or how deeply ingrained the habits they encourage, are reversible.
The child may find it challenging to move away from their value system as an adult or not wish to, ex-Mormons not infrequently still never drink coffee, but they can make an independent choice eventually.
We would object if a Christian tried to give a child a full tattoo sleeve of St Michael fighting demons.
We would similarly object to a child undergoing extreme Yogic mortification practices.
We also object to someone undertaking Femal Genital Mutilation purely because that is what their ancestors have always done, as challenging as it is to enforce.
Sitting in church and hearing a sermon is not permanent.
Having some incense burned and performing Puja in a Mandir is not permanent.
The Amrit Sanskar ceremony where a child can join the inner circle or Sikhism is not permanent.
Getting a knife to their fucking dick is very permanent. I throw out the challenge, in what other context than "Yahweh made me do it" is a cleric or one of their minions taking surgical tools to a child's penis okay?
It's special pleading. This is not okay, and the only reason it happens is because believers get violent about it.
No other mainstream religious tradition bar Abrahamic ones contains this feature. Somehow, remarkably, they manage to transmit culture, values and theology without that.
I understand its a part you don't want to abandon, but somehow the faithful managed to drop many other features incompatible with modernity. This one shouldn't be any more special.
We don't allow parents to arrange weddings for their children, as much as I'm aware it happens. We don't allow parents to sell their children anymore, no matter how much their treasured culture permits it. We don't let parents execute their children, or beat them into a state requiring hospitalisation.
There is no other context this is currently acceptable.