Sour mood grips Kremlin leaders. Moscow is scowling angrily both at the Olympic Games in Los Angeles and at East Germany's efforts to keep up detente with West Germany

Olympics? What Olympics? If you mean that unrepresentative gathering of lesser athletes in Los Angeles , that thoroughly politicized nonevent that is little more than a sidelight to the American presidential election campaign - well, you've been reading and listening to the official Soviet news media.

Moscow is not only leading a boycott of the Los Angeles Olympic Games, but it is also missing no opportunity to denigrate them. The government-controlled media have barely mentioned the Olympics; and, when they have, the context has been uniformly negative.

All this reflects Moscow's continuing campaign against the Reagan administration and things American. The sour anti-American mood has affected the Soviet Union's attitude toward everything - from youth fashions to superpower summitry.

When the press is not disparaging the Olympic opening ceremonies or discouraging young people here from wearing imported clothes that feature a Stars and Stripes motif, it can be found seeking to pin the sole blame on the Reagan administration for the current deadlock over negotiations on nuclear and space-based weaponry.

And, as a result, citizens of one of the world's most sports-minded nations are hearing next to nothing about the summer Olympic Games.

The only official acknowledgment that the games had even begun came in a dispatch from Los Angeles on Tass, the official Soviet news agency. Tass said the opening ceremony of the games was ''turned into a frankly political performance, whose organizers were billing the notorious 'American way of life.' ''

The ceremony, it added, was produced ''in the worst Hollywood traditions.''

That did not prevent US Secretary of State George Shultz from reveling in the opening ceremonies - or from taking his own swipe at the Soviet leadership which had orchestrated the boycott. After watching the ceremonies from the stands, Mr. Shultz reportedly commented, ''Eat your heart out, Chernenko.'' Konstantin Chernenko is, of course, the head of the Soviet Communist Party.

Still, Shultz's words appeared mild compared with the rhetoric pouring forth in the official Soviet media.

Using such headlines as ''the dirty games of the White House,'' Moscow newspapers have dutifully chronicled every untoward incident that has happened in or around Los Angeles.

Further, they have presented a picture of this year's summer games that is wildly at variance with other accounts.

For example, readers of Komsomolskaya Pravda (the Young Communist League's official newspaper) were told that air tickets from New York to Los Angeles cost attend the games.

At the same time, other reports from Los Angeles indicated that the expected widespread profiteering and price-gouging in connection with the Olympic Games have, for the most part, not happened, and that hotel rooms could be had for around $40 a night.

Tass reporters at the opening ceremony said the audience ''acted as if following the baton of some invisible conductor.''

While competitors from NATO countries were given ''an uproarious welcome,'' Tass reported, the crowd ''pointedly kept silence when athletes from other states appeared.''

That report, of course, failed to mention the ovations given for the teams from Romania - the sole East-bloc state to defy Moscow and appear in Los Angeles - or China, the sprawling communist giant on the Soviet Union's border that is often at odds with the Kremlin.

It also ignored the presence of Nadia Comaneci, the Romanian gymnastic sensation of the 1976 summer games, who is attending the games as the guest of the Olympic committee.

Still, on Monday, a full 24 hours after the games began, Tass did begin to carry summaries of the competition on the Olympic fields.

It gave prominent play to the gold medals won by a Chinese pistol shooter and weightlifter. The last line of the dispatch mentioned that the United States led in gold medals.

Tass also ran a summary of the winners in individual events, giving the names and countries of the winners and, where appropriate, their times or scores.

Earlier, however, Tass had indicated that the Los Angeles games are ''of a clearly unrepresentative character.''

And the Soviet press has also issued forth with critical articles, noting that the absence of athletes from socialist-bloc countries has seriously devalued the competition in specific sports - notably weightlifting and swimming.

It is difficult to determine how all this is playing with the average Soviet citizen. Russian males, in particular, are sports enthusiasts.

And while many loyally parrot the official government line - that East-bloc athletes are staying away because of security considerations - others privately question that explanation.

There are reports that many television viewers in the Baltic republic of Estonia - which can receive signals from nearby Finland - are glued to their sets for news of the Olympics.

Still, the Soviet government says that if anyone is engaged in distorting the reality of what is happening in Los Angeles, it is the American officials who are running the games.

And, after all, says Tass, they are ''deliberately hushing up the fact that the leading sport powers of the world could not take part in the Olympic Games because of the most crude violations of the Olympic Charter by the United States authorities.''