And this is amazing:

When asked why the airline had the man forcibly removed, and whether that was standard procedure in cases of overbooked flights, United refused to comment.

Instead they told BuzzFeed News all further questions should be referred to Chicago Police. BuzzFeed News contacted Chicago Police and were told to contact the Chicago Department of Aviation. When BuzzFeed News contacted the Chicago Department of Aviation they were transferred to a TSA message bank. A TSA spokesperson later told BuzzFeed News they were not involved and to contact Chicago Police.

Circles of bullshit.