The US relationship with the ICC has been quite variable. The law was passed in 2002, though it does provide for specific exemptions for specifically-named foreigners. Likewise, in 2020, the US had executive orders outright freezing ICC officials' assets, sanctioning them with OFAC, and banning them and their family members from entering the US (these were removed in 2021). At other times, the US has been somewhat supportive, if not to the extent of modifying the law or recognizing the court.
Doesn't this make the US a safe haven for other countries' war criminals?
You'd think the rule would be that there will be no support for ICC agents investigating US citizens.