So teachers are not compensated poorly. And, as the link above suggests and contrary to another assertion made by Damon, it turns out that teachers don’t work long hours. At least not compared to other professionals.
None of this is to argue that teaching is easy or unimportant. But K-12 educators are not paid poorly. They may have good reason to be mad at their collective bargaining units, however. Since 1991, teacher salaries have generally kept pace with inflation while inflation-adjusted per-pupil funding has gone up by more than 25 percent. So even as more dollars are heading to schools, teachers aren’t grabbing much of it, at least not at the same rate as the per-pupil funding increases. Their unions and negotiators may be grabbing more. Ther are more teachers per student than ever before, so it appears that part of the money is going into more staffing rather than paying existing employees more.