Organizations who buy ads on Facebook target their campaigns based on various attributes you have entered and Facebook has calculated about you. So even though you may not have entered a political preference into Facebook, Facebook will allow advertisers to target ads based on their guess of your political affiliation. You can check and delete these ad preferences by going to https://www.facebook.com/ads/preferences.
Example Facebook ad preferences page
What surprised me is Facebook guessed my political leanings incorrectly. I would rather not see ads targeted to me based on assumed politics so I deleted the preference. I deleted some other ad preferences that were humorous to disturbing like my assumed interest in “begging”, “camogie” and “hell”.
