It's worse than that - "simply bad performance" using methods that are highly unreliable and have not been validated.
The philosophy seems to be that teachers are independent, heroic, commodities. That is:
"independent" - any problems can be attributed solely to the teachers (after some normalization based on the socioeconomic class of the students), and not to the school system or other large scale system;
"heroic" - the teachers are the biggest factor in education, and it's up to the teachers to individually supply everything;
"commodities" - a teacher can easily be replaced with another teacher, with no effect on learning, the teaching work culture, or long-term community stability.
The reason for this philosophy seems to be that it's well-aligned with certain view of a free market. By casting education in this framework it encourages the idea of replacing a socialized public school system, whose goal are the long-term needs of the students and the culture, with a state subsidized for-profit system with less local democratic control that is able to transfer more money to private owners.
The philosophy seems to be that teachers are independent, heroic, commodities. That is:
"independent" - any problems can be attributed solely to the teachers (after some normalization based on the socioeconomic class of the students), and not to the school system or other large scale system;
"heroic" - the teachers are the biggest factor in education, and it's up to the teachers to individually supply everything;
"commodities" - a teacher can easily be replaced with another teacher, with no effect on learning, the teaching work culture, or long-term community stability.
The reason for this philosophy seems to be that it's well-aligned with certain view of a free market. By casting education in this framework it encourages the idea of replacing a socialized public school system, whose goal are the long-term needs of the students and the culture, with a state subsidized for-profit system with less local democratic control that is able to transfer more money to private owners.