The ICJ also rejected, by 15 votes to one, the U.S. counterclaim seeking a finding of Iran's liability for interfering with the freedoms of commerce and navigation in the Gulf by attacking ships through missiles and mines.
The Court concluded, however, that the US had not submitted convincing evidence that the missile attack on the Sea Isle City in 1987 could be attributed to Iran. In view of all the circumstances and the evidence submitted by the US, the Court found that… the mining of the USS Samuel B. Roberts was insufficient in itself to amount to an "armed attack" on the US…[and] that the evidence of Iran's responsibility for mining the USS Samuel B. Roberts was inconclusive.
If the US had destroyed an offshore rig/Iranian vessel that was actively firing on neutral/US flagged shipping, that would be justified. Thwacking offshore installations because “they shady af, trust me bro” is not a legitimate use of force