The Bills could have hired a hack, who could have spent weeks crafting his "ass" logo.
A lot of times what happens is a designer presents his logo design, and then everyone needs to put their fingerprint on it. Then it turns into "ass."
There are also a lot of bad designers in this world. It's not like Buffalo is a hotbed of top creative talent. This isn't New York, San Fran, Minneapolis, Portland, etc.