In the case of a court there has presumably been a taking of and weighing of evidence. So theoretically at least the authority from which it argues is authoritative.
Not saying that’s the case in this instance.
It should be obvious in hindsight, given the news fabrication practices that have been exposed today, that this was just another Deep State con job. Destroying whatever was in that Chinese embassy must have been very important to them.
A UN-linked court? More like the opposite. The ICJ is yet another derivation of the USSR, like the entire UN (thanks to Alger Hiss).