Fight to be Respected as Professionals
Teachers fought for professional respect for most of this country's history. Progress in education depends largely on the preparation and effort of the teacher. Yet, teachers were not treated as a profession worthy of that respect for many years.
Teachers suffered from low pay, difficult working conditions and very little job security. For many years, they presented themselves as professionals in the hope that they would treated accordingly. For many years, they had to work with rules similar to the ones posted here. It's no surprise that felt the need to unionize.
The National Education Association provided teachers with professional training. Teaching is a difficult job and those who decide to make it their career are dedicated people.
Though there is no source for the rules attached, many school districts had similar rules through the early 20th century, prompting teachers to work to earn the respect they weren't being given.
After decades of asking to be treated like professionals, teachers gained very little. Even in 1970, average starting salaries for teachers were $2000-3000 less per year than the starting salaries men with bachelors degrees could receive in any other profession. It's little wonder that teachers unionized to get fair compensation.