Not necessarily. I'm not referring to no-research universities, which do have much higher teaching loads (although still not ridiculous. Teaching 3 or 4 classes a semester is hardly strenuous). I'm referring to research universities that aren't in the top 100, but which still push out graduate students.

My undegrad Alma Mater, Kansas University, for instance. Professors teach 1 or 2 classes a semester, with TA support (really, when you have TAs, teaching is not real work). They are still expected to do research, but the pressure is much less than at a top 50 school.