IT IS ALWAYS a pleasure to be able to report good news about the United Nations. The current occasion is the acceptance of a critical report on Afghanistan by its Commission on Human Rights. It was already a plus that the commission last year overcame Soviet-built and procedural obstacles and authorized its first specific account of abuses perpetrated by the Soviet invaders of Afghanistan and their client government in Kabul. Now the report has been submitted to the human rights body and accepted by a vote of 26 for and 8 against (including -- why? -- India), with 8 abstentions.

In a more ideal world, it would not be surprising that a representative international body, having looked at the best evidence available, would condemn the perpetrators of Afghanistan's agony. The United Nations, however, to put it mildly, is not that ideal world. In areas where the Third World and the communists find common cause, their transgressions are usually noted, if at all, almost inaudibly. The real and imagined sins of the Western nations and their partners are pursued with vigor -- often with venom too. This pattern has led to a special effort by the Reagan administration to apply a single standard in judging allegations of violations against different parties.

In this instance, the administration was aided by the fact that the victim is a Third World state. Soviet aggression against Afghanistan is an issue -- Vietnam's invasion of Cambodia is another -- where the communists and the Third Worlders split. For six years, large majorities at the United Nations have condemned Soviet policy. To freshen the issue, it was decided last year to launch an investigation in the Human Rights Commission. Afghanistan refused to cooperate, but Pakistan facilitated access to the refugees whose numbers and misery in themselves are evidence as stark as their testimony of Soviet terror.

For his painstaking report, Felix Ermacora, the Austrian law professor who compiled it, was called a neo-Nazi by the Soviet delegate. The personal smear on an international civil servant, who under the rules cannot defend himself, presumably reflects the Soviet Union's finding that there were no valid objections to the substance of the report.

The document states "profound concern at the grave and massive violation of human rights in Afghanistan" and "distress . . . at the widespread violations of the right to liberty and security of person, including the commonplace practice of torture against the regime's opponents, indiscriminate bombardments of the civilian population and the deliberate destruction of crops."

These are the facts in Afghanistan. It is necessary for everyone to know them.