A common intactivist argument against the routine circumcision of infants is that circumcision is an unneeded and risky procedure.
The common strategy of the pro-circ community is to argue to just one of the 2 components of that statement, in order to keep those two words separated: i.e., ignore the "unneeded" word and argue that every surgery is risky, or ignore the "risky" part and argue for the benefits.
If they let the two words stay together they lose the battle.
The problem with the benefits is that at best, they are merely preventive medicine for things that may or may not happen in the long future. However the risks are immediate and may negatively impact the whole life of the infant -and his parents.
Let's take a bad case scenario. Let's assume that the parents are either circumcising because they believe in the preventive benefits of the procedure or because they have never really questioned whether circumcision is necessary or not. Let's say the procedure goes wrong: the baby dies, or suffers a necrosis of the penis (and has to have it removed) or has part of the penis amputated. These things happen. If you were the parents of this hypothetical baby, wouldn't you be crushed? Would the potential benefits justify a lifetime of regret?
The thing is, yes, every surgery has risks. You normally have to weight the risks and the benefits to make your decision. If the worst possible risk is death, then the benefit better be to save you from an immediate danger; if you are not in imminent danger why would you risk your life? Furthermore, if your baby is not in any immediate danger and he relies on you to live, why would you risk his life? But circumcision, in most cases is not about saving a patient from an immediate condition that endangers his life, especially not when done as a routine practice. However the risk is always there.
When someone argues in pro or against something, it's always useful to understand the person's motivation to argue in that sense. Try asking a pro-circ why they personally favor circumcision.