He ("he" is correct; I was confused by the given name at first until looking the person up with a Google search) should blame the typical master contract with the teachers in the school district for that. That is a standard contract provision recommended by schoolteacher unions whether a state has a "union shop" or "right-to-work" rules. Usually, school districts cave in and adopt contract provisions like that, because in states where a union shop is not mandatory, and collective bargaining for public employees is not mandatory either, schoolteacher unions are still very influential political interest groups that can swing voter turnout in the typical low-turnout school board election. School boards have a lot more electoral incentive to align with the interests of schoolteacher unions than with the interests of learners. (The interests of learners align with favoring better teachers over worse teachers, rather than with favoring senior teachers over newly hired teachers.)
The crucial voter action influencing the daily lives of teachers at work happens not at the federal level
http://educationnext.org/the-election-contests-that-really-m...
but at the state level and local level, where most of the funding for schooling is set (and what proportion of funding goes to anything other than staff compensation, by far the largest line item in any school budget, is set) and where work rules, especially priority for promotions or layoffs, are set.
There is considerable evidence that seniority rules lead to higher numbers of teacher layoffs than would be necessary if administrators were allowed to make effectiveness the determining factor in issuing layoff notices, rather than length of service.
http://educationnext.org/seniority-rules-lead-districts-to-i...
A teacher who is doing a good job helping students learn is worth his or her weight in gold, but seniority doesn't match teacher quality sufficiently well to be the sole basis for determining promotions or layoffs in a particular school district. Actively identifying the most able teachers and encouraging the least effective teachers to find other employment, regardless of seniority, could do much to improve the efficiency of the public school system and free up resources to reward the best teachers better than they are rewarded now.
http://hanushek.stanford.edu/publications/valuing-teachers-h...
My Google search to verify the teacher's background turned up this post from the teacher's blog
http://mgmfocus.com/2012/10/21/i-used-to-love-teaching/
covering some of the same issues, with a different slant for the blog's different audience.
"I give up. They win. I have joined the ranks of parents who have come to realize that we are only empowered to do one thing: take care of our own. I hope that things change, but I don’t have the energy, the money, or the time to continue beating my head into a wall. And if the choices have run out for my toddler when he’s ready for school, I will do it myself. Maybe I’ll do it for others, as well. Who knows."
AFTER EDIT: Thanks for the several interesting comments. Wisty asks how teachers might be identified as effective teachers in the interest of making more effective teachers available to students. The same scholar of education policy I linked to for the general point that effective teachers make a difference has written extensively about identifying those teachers. These links
http://hanushek.stanford.edu/publications/effective-teacher-...
http://hanushek.stanford.edu/publications/teacher-deselectio...
from his website (which link in turn to longer-form formal articles on the issues) are a sample of the research on the subject. Identifying teachers with good "value-added" is not at all easy, and there are immense incentives to cheat while attempting to identify such teachers, but there is also an enormous payoff from doing better than is done now in identifying effective teachers.