Firstly, the movements are all over-exaggerated. Obviously he does not have a good grasp of sign language. (No surprise that he would not take the the time to learn proper "pronunciation" since he's just exploiting it for his own personal gain.) For example, the beard sign doe not extend very long like the way he does it. Secondly, the other two signs he uses are uncommon and out of date and would only used in a derogatory way, the same way someone might still refer to African Americans today as "colored" or "negro."
Lastly, did he (or you) even stop and think for a second that there are plenty of Deaf people who also happen to be Jewish? What he is doing is othering the Deaf community here, making them seem like a different, removed group of people from society, and an ignorant, bigoted group of people at that.