With the caveat that I think RIC is unjustified crap, here are the three arguments that I think are most compelling-sounding:
1. Probable marginal reduction in STD rates, notably HIV
2. Decrease in associated complications (e.g., phimosis)
3. Relative ease of the procedure in infancy vs. when grown
Those are the best three I can come up with. Again, I think this reasons don't come close to justifying RIC. However, they're probably your best bets rhetorically. More than anything, I think it's stupid that a class would assign you an
opinion on a topic. It's not like we need to teach people specifically how to be disingenuous and hide that in rhetoric.
I'd look for better sources than the linked PDF. I Googled the web site, and it's apparently published by the "Gilgal Society," a circumcision advocacy club with a Hebrew name referring to a Biblical hill of foreskins. Seriously. In any case, a three-second scan indicates that they're cherrypicking medical studies in an indefensible way. It's not reliable, even by the standards of disingenuous papers.
Good luck I guess, even if I respectfully hope you get your ass kicked by the paper with the right position.