Japan is a big country and there are people with diverse views in it. Overwork is widely recognized to be a societal problem here, in the same fashion that e.g. racism is widely recognized to be a problem in the US. You could certainly find people who disagree with either conclusion, but you could also find people who disagree that the earth is round.

There exist government employees whose literal only job is preventing deaths from exhaustion. Japan has at least a few hundred of these a year; the true number of excess overwork-caused death is probably low tens of thousands when you factor in suicides.