Califonia law calls for any person who goes out in public to use a confront masking, even if they go to a cafe or cafe. Lenin also posted a video saying his side of the story during the said incident.
In the customer's post, Amber Lynn Gilles said barista Lenin Gutierrez refused to serve her when she entered without a face covering.
The post has been shared thousands of times and racked up hundreds of thousands of comments.
Despite the criticism heaped on her, Gilles doubled down.
The self-described activist and yoga instructor did not respond to a request for comment, but made clear in multiple posts that she rejects medical data and science showing masks curb the spread of the coronavirus.
San Diego County requires everyone to wear face covers in public, even when picking up food at restaurants or shopping at a store, to prevent the spread of the coronavirus.
As of Thursday, 196,046 people in California had tested positive for COVID-19 and 5,726 had died, according to data compiled by Johns Hopkins University.
The team of researchers calculated that the use of a face mask prevented more than 78,000 infections in Italy between April 6 and May 9 and more than 66,000 infections in NY between April 17 and May 9.
Cowan later explained via the GoFundMe campaign that he is "Raising money for Lenin for his honorable effort standing his ground when faced with a Karen in the wild". It's already raised more than $US22,000.
"Everybody is rallying around somebody for doing what they're supposed to do and trying to protect everyone else", Cowan said in an interview with KGTV.
"People don't ask you to do much, they ask you to wear a mask for your own safety and the safety of others", Cowan told CNN.
"It's so shocking to see something get so big that only happened within a few minutes", says the barista, Lenen Gutierrez, in a Facebook video.
Gilles, for her part, has commented repeatedly on Facebook that she's not backing down from her anti-mask stance. She later photographed Gutierrez, asked for his name, and said she meant to call corporate. She was then, labeled as the new 'Karen, ' or when a middle-aged White woman is associated with rude and obnoxious acts against another person.
Gutierrez said he plans to use some of GoFundMe's money to pursue his dreams of becoming a dancer. "The fact that now it went over $65,000, I don't know how to truly vocalise how grateful and blessed I feel with this opportunity everyone has given me". "Make sure you go live on Facebook so that everyone can witness the public humiliation in its entirety, and bring a step stool as well; it's going to be a mother on your ankles when you come down off your high horse", said another user.