Bunny lore. Most RL bunnies are Black and Latino, who take a certain pride in 'dancing' through their work. (I'm sorry if I sound like an apologist for slavery here.) Many of them know ASL, and use it, or an adaptation thereof, because it's hard to hear over the incessant fans, etc. in a clean room. People also, thus swathed, also tend to lose all sense of 'personal space' or body taboo, and weirdly, end up touching each other a lot more than most people do in everyday situations.
Source: Rudy Rucker.