I'm guessing there is some specific context to this that is not clearly specified here.Honestly, everyone should be respected as a human being. No matter how wrong someone thinks an individual is, the moment you dehumanize them proves that you are are no longer human yourself. To dehumanize, is the worst thing you can do to anyone. Because when you dehumanize, you stop seeing someone as rational, and interpret everything under extreme bias. Your empathy turns off, and they become fodder to your own selfish whims. I assume people in power tend to go through this cycle at one point. They become so enriched, and supported by an echo chamber. That they no longer see their adversaries as human, and just mow them down with complete ignorance to their suffering, and disregard their complains and fears as "Conspiracy".
I don't really think firmer approaches--even harsh ones--necessarily indicate a lack of empathy. Sometimes you do need to shut people down, or "mow them down" as you put it, because it's the only way to get them to stop crossing boundaries. Furthermore, sometimes things are done out of "tough love" such as disciplining your kids. Not to mention, sometimes people simply get a bit emotional and say things.