Plein issued an apology to the writer on Instagram.
"That's exactly why the [Bronx] and Queens sent me here," Ocasio-Cortez tweeted.
Prada-owned Miu Miu is the latest, but Urban Outfitters, Zara and Umbro have sparked fury in the past.
Employees at the factory in China typically work 60-hour weeks according to an audit by inspectors.
In a Wednesday email, the candidate accused the media of spreading "false" and "misleading" information.
The money raised will go to a charity that helps disabled people participate in sports.
Four years after his booze-fuelled, anti-Semitic rant the bad boy of British fashion is back.