From Townhall:

CRPC decided to share a Fox News piece detailing the research they conducted on their Facebook page. The organization wanted to boost their post as an ad so more people would see the study’s results. That’s when Facebook’s bias became clear.

One of the ads CRPC posted was a direct link to their website where people could download the study’s results. Facebook quickly approved the ad and all was fine.

When the organization went to post an ad linking to a Fox News article that detailed the study’s results, the ad was not approved.