The goal posts have been set by the original issue: whether circumcision harms the person or benefits them.
The main people who can answer that are adult males who were circumcized.
I am confident that if you asked 1000 religious Orthodox Jewish men whether they would have preferred to NOT have been circumcized at 8 days old and instead had to choose it later, an overwhelming majority would say they were glad they were circumcized that early. And they prefer that over never having been circumcized.
I would be hesitant to say the same about non-Jewish men. The reason Jewish men are happy about having been circumcized early is because (perhaps this sounds ironic) it gives them FAR GREATER CHOICE when it comes to their own community and membership in three thousand year old people, marriage and - above all for most religious people - serving God in the way spelled out in the Torah.
They can choose to leave the lifestyle or increase their observance etc. much more easily since one of the biggest challenges is already out of the way.
You can of course tell them they don't understand what real choice is, that this is stockholm syndrome and that religion is mass delusion.
But they may not agree and they collectively are ultimately the judges of what was better for them.
It is a different conception of morality and rights than the individualism that comes out of the Scottish Enlightenment
These ideas that a parent "knows better" because they - and millions of others - were in the same situation and are glad this was done, are valid.
It is a collective morality of a people. And again I would say that unless they believed that God commanded it, it could be possibly changed but as it is, when the vast majority of complaints are from the OUTSIDE of the community, perhaps the downsides far outweigh the upsides.