So the idea is that not consented mutilation is defensible as long as the consequences after a few days or weeks are extremely minor? Just repeating this back to you so we're on the same page.
I'd say that attempting to prohibit this tradition has a net negative impact on the integrity and functioning of society because the harm in question is very minor but the reaction to such an attempt will be major. I'm sure you are trying to twist this into "but then I could anesthetize and then circumcise you", however, in that case I'd retaliate so drastically that it would negatively impact the functioning of society much more than say 100 circumcisions, hypothetically speaking.
Focusing only on empathy often misses the point too as it tends to get politicized, overinflating minor issues as in this case, which will ultimately result in power conflicts, degrading long-term sustenance.