Because freedom doesn't knock. It rings.
There's none. They both knock on the door, but never goes in!
They have no hands to knock on the door.
Not enough cement EDIT: Okay thanks for pointing out that I messed up the wording but the joke is supposed to be the funny part
The color. Yes, this is an anti-joke. Downvote please.
Freedom.
because freedom rings. Happy Independence day everybody!
Ring Around the Rooooozaaay.
Because they both have rings.
Warning: Gore