The left-wing advocacy group Media Matters for America is being bankrolled by some of the biggest Democratic megadonors in the country, according to a new report. The Washington Free Beacon reported Thursday that Media Matters, a liberal nonprofit often cited by legacy news organizations as a media watchdog, might have “mistakenly” identified some of its biggest donors in a November filing to the New Mexico attorney general’s office. According to the filing obtained by the Free Beacon, Media Matters’ biggest donor was Deborah Simon of the shopping mall giant Simon Property Group, who gave $4 million to the nonprofit. As...