Piano "proficiency"

As a student in the Conservatory of Music, I am required to take 4 semesters of piano classes, and then pass a final proficiency exam. There's just one problem. I don't play piano. The first instrument I ever played (as far as taking lessons and practicing and whatnot) was piano. I was probably about 8 at the time and was really excited to play the piano and make music. My lessons lasted a few months - I was horrible! I was so excited then, when I got to started playing bass when I was 10 or 11. Finally, an instrument that makes sense and is fun! So I practiced hard, played in lots of different orchestras and groups, took lessons, got accepted into the UMKC Conservatory of Music with a scholarship in music, and then... I found out I had to take piano. But I play bass- that why I wanted to study bass at the Conservatory. If I had wanted to play piano, I would have played piano. And now that I have suffered through 4 semesters of piano classes, ranging to the insanely mundane to the insanely difficult, I vow that I will never play piano again. So why did I have to take piano classes?