As far as why someone would teach a bird to swear... in households that consist of only adults who are rather insensitive to swear words, a bird that swears can be very entertaining. I had a Mitred Conure, Ollie, who picked up "F___ It!" shortly after we got him. It was hysterical, especially since he would say it when it seemed completely appropriate.
That being said, I don't necessarily condone teaching swearing to birds, since there will always come a time when that swear word will come out when it's NOT appropriate, like around children or rather conservative family members or friends that may find it "not funny".
I miss my Ollie! He was prone to very deep sleep... to the point of falling off his perch sometimes. After several years in my care, he fell off his perch backwards one night and broke his neck on his water dish. He died in my hands a few minutes later. So sad.
