Yes, the tone matters. A lot.
For leaders, the tone is the measure of *formal* respect for the people working for them, because in working env we could say nothing about the "real" human respect. So at least the "formal" respect is the only thing that remains.
So it is absolutely mandatory in working enviroment. No excuses. Would like to be a good PM ? Be polite AND firm, evoke the goals, show the necessary path, motivate, even clearly disagree, but... Respect the people.
Adding colours, to be rude often match to be not so technically brilliant. 
Courtesy does not cost, and gets a lot, as well as being morally a duty.
He did well leaving.

"Chi semina vento raccoglie tempesta"
"Who seeds wind shall harvest storm"