The finding seems to be that jerks cause toxic work environments and non-jerk bosses (i.e. "ethical leadership") do not. Unfortunately, hoping that leaders are

The finding seems to be that jerks cause toxic work environments and non-jerk bosses (i.e. "ethical leadership") do not. Unfortunately, hoping that leaders are not jerks isn't useful advice: if a jerk is appointed and supported from above the damage is mostly already done.