Earlier quoted context omitted.
Someone with a masters in education may or may not have the knowledge required for a particular subject, say a math or science. Or another way, just because someone has a masters in education doesn’t mean they can teach any specific class. Their background could be in counseling, administration, school psychology, or education methodology... not, for instance, typical high school subjects.
A degree in anything but the subjects they teach? Does that mean that a high school physics teacher knows nothing more about physics than high school physics?
Probably not; the state policies adopted under the pressure of NCLB and it's successors put strong pressure on districts to hire teachers with at least a bachelor's degree in the field taught for secondary schools, and even teachers that don't will often have additional coursework as part of college breadth requirements.