I'm American and I never once agreed to any of our laws. Countries have a monopoly on violence, that is it. You can agree, disagree and try to survive or hope some other country will let you immigrate.
That being said, I think the vast majority of Americans are ok with the ICC holding people committing genocide accountable. Most Americans also do not like the influence Israel has on our country and these sanctions are just yet more proof that we are occupied and not even operating in our government's own interests.