Glock and Hellen Keller

Alright, listen up buttercup. This "joke" is about Helen Keller, who was blind and deaf. The joke is that the person told her a Glock (a type of gun) was a hair dryer. Since she couldn't see or hear, she wouldn't know the difference. This is funny because it's dark and mocks a disabled person. You wouldn't get it, because you have zero IQ.