"Woman thinks Rihanna’s eyebrows are racist."

Scarlett Johansson playing a transgender character? Unacceptable. 

Zac Efron sporting dreadlocks? Racist. 

A high schooler wearing a Chinese prom dress? Problematic. 

Thus spake Twitter. Users of the outrage-addled social media platform have collectively proved highly sympathetic to claims of "cultural appropriation." But they seem to have finally drawn a line in the sand, and it is somewhere before Rihanna's skinny brows. 

The person who discovered the ineffable threshold was Marie Claire social media editor Krystyna Chavez. In an article last week for the women's magazine, Chavez accused Rihanna of cultural appropriation for recently debuting the so-uncool-it's-cool eyebrow fashion. 

Chavez wrote that she had been "deeply confused" and "deeply annoyed" to see the black pop star flaunting what she sees as a Latina look on the cover of this month's British Vogue.

“Wait, WTF?” Chavez recalled thinking on seeing the fashion magazine. "Why is Rihanna wearing chola brows?"

It is unfair, Chavez argued, that Rihana was able to instantly transform finely threaded brows into high fashion, whereas a Latina like herself would be deemed "trashy" for sporting them.

"As a minority, I know I’m always one step away from being judged negatively based on how I look," Chavez said. "I know that if I stepped out with these brows tomorrow, I would face such intense judgment that would just feed into the negative stereotype many minorities work very hard to avoid."

Chavez explained skinny brows have always been off-limits to her and "thousands of other Mexican and Mexican-American girls." Growing up in Los Angeles, she said, they were reserved for "cholas" or female gang members.

Despite acknowledging that skinny brows transcend the Latinx community -- and have roots in South African ​culture, Roaring Twenties fashion, and the Harlem Renaissance -- Chavez said that "for the Latinxs among us who have faced persecution for our appearances for decade—and for the cholas I knew growing up who took immense pride in their look—we will only ever see chola brows, no matter how much you dress them up."

At least one person -- whom Chavez cited in the article -- sort of agreed with her. 

But there was scant evidence for her claim that other "Latinxs across the internet voiced their frustrations at the double standard" or for attempts by some conservatives to conjure a left-wing mob descending on Rihanna. 

In fact, it was the other way around. Condemnation of Chavez' article reigned down from across the political spectrum. 

National Rifle Association spokeswoman Dana Loesch was typically blunt. 

A lot of people were annoyed that Chavez felt the need to go ahead with her article after admitting that skinny brows were not an exclusively Latinia phenomenon. 

Still, Twitter managed to find a way to make the conversation at least partly about identity politics. 

A number of South African women said that if any group has a claim to skinny brows, it is them -- and particularly grocery store clerks from their country.

Some black women wanted to know how Latinas could be possessive of eyebrow tweezing while also feeling free to drop the N-word. 

And so Twitter again returned its natural state as a war of all against all.