Earnestly, and with applause from journalists, politicians are saying about AIDS: candor, regardless of the cost. But truths are being blurred because they inconvenience a political agenda and shock sensibilities. The agenda is to avoid giving offense to any groups and to avoid the accusation of ''discrimination,'' even when the accusation is unwarranted.

In spite of much talk about the ''breakout'' into the general heterosexual population, AIDS still is and probably will remain predominantly a disease of homosexuals and intravenous drug users. It will decreasingly afflict educated, information-receptive homosexuals. It already is disproportionately, and will increasingly be, a disease of inner-city blacks and Hispanics.

Blacks and Hispanics, who constitute 11 and 8 percent of the population respectively, are 25 percent and 14 percent of AIDS patients. Those percentages probably will rise because AIDS is a behaviorally based disease and will disproportionately afflict those disadvantaged inner-city classes least able to acquire and act on information. After all, many people are caught in the culture of urban poverty precisely because they have never been given the basic skills of social competence: they do not regulate their behavior well, least of all in conformity with public-health bulletins.

Americans have a technology fixation generally. Regarding health, their thinking is shaped by the polio paradigm, the conquest of disease by Dr. Salk's silver bullet. But America's principal public-health problems flow from foolish behavior regarding eating, drinking, smoking, driving -- and, with AIDS, abuse of the body, especially the rectum.

Most journalism about AIDS reflects social and political squeamishness. In addition to an understandable reluctance to discuss certain sexual matters, journalism is infused with liberal values, including abhorrence of ''discrimination,'' which is defined (indiscriminately) to include all invidious distinctions among social groups, particularly those, such as homosexuals, that have a history of being badly treated.

Journalism seems reluctant to clarify that the primary reason for the AIDS epidemic is that the rectum, with its delicate and absorptive lining, is not suited to homosexual uses. The nation needs unsparing journalism of the sort found in the Chicago Tribune Magazine of April 26:

''. . . 81.5 percent of the second cluster of AIDS patients had engaged in the practice called 'fisting,' which causes rectal trauma, in the years before they fell ill. The researchers defined fisting as the insertion of a portion of the hand -- or even the entire fist -- into the anus of another person. The 27 men studied had a median of 120 sexual partners during the year before the onset of symptoms, with one man reporting up to 250 sexual partners in each of the three years before symptoms.''

Without here adding details about dildos and enemas, suffice it to say that the data suggest that receptive anal intercourse is the major, if not the only, important exposure by which homosexuals acquire the infection. In many cities, homosexual organizations have effectively taken the lead in distributing information about safe sexual practices. And, of course, not all homosexuals are promiscuous or given to high-risk behavior. However, even some who are not are dismayed by dissemination of information about those who are. And insufficient information about homosexual practices has impeded understanding of the epidemic.

Time and energy are being wasted on the political project of spreading the false message that the AIDS epidemic does not disproportionately involve particular minorities. British billboards proclaim: ''AIDS Doesn't Discriminate,'' a message designed to absolve homosexuals and addicts of disproportionate responsibility for the epidemic. In New York City, print ads portray a heterosexual couple tangled in sheets, with these words: ''Bang, You're Dead!'' Such ads are a disservice to the extent that they distract attention from the fact that fewer than 4 percent of AIDS cases have resulted from heterosexual contact.

Indifference and carelessness could lead to an exponential growth in AIDS cases among heterosexuals. However, today the rate of heterosexual transmission is increasing primarily among black and Hispanic teen-agers whose sex partners are intravenous drug users. New York City has one-third of all AIDS cases; 36 percent of the city's cases are IV drug users. Half of the city's 200,000 addicts are thought to be infected with the AIDS virus.

Of course anyone with AIDS deserves care and compassion. Of course testing is acceptable, if only marginally important, for applicants for marriage licenses and citizenship, and for prisoners. (Many rapes are homosexual rapes in prison.) But while it is politically safe and socially soothing to pretend that AIDS is now a democratic, meaning universal, disease threatening us all equally, that is false.

So is the notion that the most urgent task is to fund research for a vaccine. Of course research should be funded generously, but dollars spent getting addicts off needles and onto methadone will do more good, as will journalism that does not trim the truth to spare our feelings.