Now we know the truth. The infamous “Compton Cookout” at UC San Diego, where members of the Pi Kappa Alpha fraternity invited guests to celebrate Black History Month dressed as their favorite ghetto stereotypes, was not an isolated incident. Nor can it be chalked up to standard-issue frat behavior, in which a degree of misogyny, bigotry and drunken insensitivity is often shrugged off as normal college hijinks.

Days after the cookout, the editor of the Koala, a campus publication known for mocking Muslims, Latinos and Asians, appeared on the university’s student-run TV station to defend the event. While on the air, he referred to offended black classmates as “ungrateful niggers.” The following day, a sign with the words “Compton Lynching” was found at the TV station. And on Thursday, a noose was hung in the Geisel Library.

At parties, on air, in public -- anything goes, it seems. It turns out the problem wasn’t just a singlepartybut an all-too-permissive culture in which some UCSD students apparently feel free to express racial malice with a breezy, unconcerned openness.

On Monday, the university announced a plan to address the growing racial tensions. It includes making greater efforts to recruit minority faculty, forming a commission to address the campus climate, ensuring ongoing funding for the chancellor’s diversity office, creating an African American Resource Center and establishing quarterly meetings between the administration and members of the Black Student Union. Many of these recommendations are not new. They were put forward by the Black Student Union as far back as 2006, when students warned they were becoming increasingly uncomfortable, alienated and even fearful on campus.

Better late than never. But there is a reason students at other UC campuses are also holding sit-ins, demanding accountability from their chancellors and calling emergency meetings in solidarity with UCSD students. In interviews with The Times, minority student leaders up and down the state said the racial atmosphere on their campuses is little better. Students at UC Berkeley and UCLA, for example, spoke of “border parties” that require attendees to hop a fence or cross a “border” to gain admittance.

In 1996, many posited that racial tensions would increase after passage of that year’s Proposition 209, which barred California’s public universities from considering race and other factors in admissions; indeed, the number of black and Latino students quickly plummeted, and it seems, in retrospect, that the skeptics may have been right. If more chancellors sit down with their students in the coming weeks, they may be surprised to learn of the “Compton Cookouts” in their own backyards.