But a pretty good philosophy of government.
No it isn't because it's shortsighted and infantile. It negates to note the consequences of indirect damage caused by people "doing their thang" which is a real cost of doing business in a society.
It is a simplistic slogan for simple minds, but it is not an accurate or sensible philosophy of government. Government cannot be neutral in the struggle between good and evil, it must take a side or it will be swept away along with any populace so foolish as to follow such a governing philosophy.