SAN FRANCISCO — Since 2013, Matt Bors has made a living as a left-leaning cartoonist on the internet. His site, The Nib, runs cartoons from him and other contributors that regularly skewer right-wing movements and conservatives with political commentary steeped in irony.One cartoon in December took aim at the Proud Boys, a far-right extremist group. With tongue planted firmly in cheek, Mr. Bors titled it “Boys Will Be Boys” and depicted a recruitment where new Proud Boys were trained to be “stabby guys” and to “yell slurs at teenagers” while playing video games.Days later, Facebook sent Mr. Bors a message …
