When did teachers become bums? When did it become okay to vilify an entire occupation — three million college educated professionals working as hard as anyone to make the world a better place?

It wasn’t that long ago that teachers occupied a quasi-secular-sainthood. It was the underpaid, overworked teachers who guided, inspired, succored, and cajoled every one of us to find in ourselves that bigger person we all long to be.

But lately it’s become acceptable, even sport, to blame teachers for all of the ills of American education.

The new documentary, “Waiting for Superman” is just the most recent salvo in a broad-spectrum campaign to demonize teachers, teachers’ unions, and public education in general. It is a blinkered caricature of life for five underprivileged students, with teachers cast as the villainous Simon Legree.

Indeed, it is amazing what a rapid turn-around the film represents in the public narrative about teachers: from near-adulation only a few years ago to ill-concealed contempt today.

In truth, it is teachers who have held education together in recent decades against a seemingly endless deluge of social pathologies. Consider just a few examples.

In the past thirty years:

Most mothers have joined the workforce. No more Mrs. Cleaver at the door with warm cookies and milk and help with Beaver’s homework.

We’ve surrendered our children’s socialization to television, video games, the Internet, and on-line social media.

America jails more of its population than any country on earth — a sign of an almost psychotically violent society. One in thirty children has a parent in jail!

We’ve absorbed the largest wave of immigrants in our history, many speaking no English and with little educational background.

Many of the best teachers, especially women, have found opportunities in other fields that were not open to them before.

Forty-five million Americans live in poverty; one of five American children are raised in poverty; one out of every eight Americans are on food stamps. The middle class is dying.

It’s pretty hard to teach a kid who has been raised by the television, when he hasn’t eaten breakfast, when the family has been kicked out of their home, when he has to work a job to help feed the siblings, when the parents have just gotten divorced or lost both of their jobs, when no-one at home speaks English, or when their most alluring role models are dope dealers, pimps, or gangsta rappers. Imagine, then, trying to teach a room full of such trauma cases.

Yet, for many of our lowest-performing schools, that is the world we actually live in. Trying to teach in that world is like trying to put up a tent in a hurricane. No sooner do you get it up than it comes right back down again. And the force factor is increasing. But teachers continue to do it.

Finally, let’s be honest about the motives of those behind the teacher-bashing.

We spend almost $750 billion each year on public education. Enterprising capitalists want to get a piece of it. A little known loophole enacted at the end of the Clinton administration allows wealthy investors to double their investment in only seven years by providing the funding for building charter schools.

That’s a 10 per cent annual return compared to less than 1 per cent available in conventional bank deposits. And the investment is essentially foolproof since it is public spending that assures the payback.

Now, making a profit isn’t a crime in a capitalist country but isn’t it funny how these “reformers” always cast their motives as altruistic? These “philanthropists” include the Walton Family Foundation, the Bill and Melinda Gates Foundation, and some of the wealthiest hedge fund managers in the world — yes, the same wizards who brought us The Greatest Economic Collapse Since the Great Depression.

It is they, fronted by President Obama, who are behind the charter school movement. Their goal is to make franchises of our schools, docile, low-cost industrial robots of our teachers, and McStudents of our children. This, despite the fact that the best academic studies of charter schools have shown that they perform no better than public schools and in many cases perform worse. Sometimes much worse.

A 2009 Stanford University study surveyed results for schools teaching more than 70% of the nation’s charter school students. It showed charter schools performed better than comparable public schools in 17% of the cases. But they were more than twice as likely to perform worse, in 37% of the cases.

That doesn’t matter. What matters is getting in on the big money.

In truth, the motive of the charter school boosters is the same profit motive that destroyed a once vibrant public health system, replacing it with the highest cost/lowest quality system in the industrialized world. Now they want to do the same for education. And the bonus add-in for them is that in the process they will destroy one of the most potent democratizing institutions in the history of America: public education.

But in order to make the sale, they have to demonize teachers first.

Are there bad teachers out there? Of course there are! They should be fired. By sheltering incompetent teachers, the unions are only giving ammunition to those whose motives are far more base than mere incompetence: making a profit off of your children. That is the reality of the public debate about education and teachers today.

Teachers don’t teach in a vacuum. Education isn’t some Immaculate Conception that occurs in a classroom, untouched by the world around it. And fast-money billionaires don’t invest for the warm-and-fuzzies.

If you want better schools, work for more stable incomes, families and neighborhoods. Get involved in your schools. Fire the few bad teachers but support the overwhelming number of good ones. And don’t be suckered by those peddling venom in the guise of altruism. Your children are products to them, pieces of meat on an assembly line whose only purpose is to produce profits. We can be better than that.