I'm not just technically correct. I'm completely correct. Not only did NATO attack Serbia, NATO countries went to the UN before and tried to get UN approval for an attack. The premise was rejected. The attacks in Serbia, whether you agree with them or not, were unprovoked, unilateral aggression by NATO on a non-NATO country. The first, but not the last.
We can't claim that Russia makes an "illegal" invasion into Ukraine if we don't accept that NATO's bombing of Serbia was also a war crime, and the US invasion of Iraq as well. The US is currently occupying 1/3 of Syria.
There is either international law for everyone, or there is no international law. Currently we have the latter. The illegal attacks we in the west made first have emboldened dictators in other countries to find flimsy excuses to invade. Sadly, their flimsy excuses are better than ours were. We have no moral standing.