Why does the writer of the following paragraph describe the other bands as “low-rate” and “amateur”? The concert festival was a failure in all ways but one: ROXXOR gave a fantastic performance.

Why does the writer of the following paragraph describe the other bands as “low-rate” and “amateur”? The concert festival was a failure in all ways but one: ROXXOR gave a fantastic performance. Throughout the day, the festival planners angered guests by running out of food and drinks, offering only muddy corners under insect-infested trees for shade from the hot sun, and act after act of low-rate, amateur bands. But then, when the fans had just about had enough, ROXXOR took the stage. The lead singer enraptured the crowd with his lyrical voice, the drummer pounded out energetic rhythms, and, finally, the people began to cheer.