So you have no way of knowing what it was like to be uncircumcised, and yet are able to conclude there are zero side effects without anything else to compare circumcision to? I'm guessing you and logic are not close friends.
You might want to read into the functions the foreskin was created through many millions of years of evolution to provide. Or read the opinion on the procedure from countries that do not practice it routinely. Ones unlike the US, which started it to curtail the scourge of excessive masturbation. Being circumcised myself, I'm horrified to have a naturally occurring piece of my body removed without given a choice in the matter.
Interestingly enough, men's rights groups aren't the only ones who are interested in the topic. Some of the strongest anti-circumcision voices I've heard have come from dyed in the wool feminists.