The Tsarnaev brothers committed an atrocious, evil act against humanity. Tamerlan Tsarnaev died by the very violence he perpetrated. Refusing to bury his body, harassing those who made his burial possible, does not make America stronger.
Did Eichmann and Hussein receive true justice by appearing in courts of law and sentenced to death under the rule of law? Was Osama bin Laden notably and unceremoniously treated to a revenge killing for his crimes?
Plenty of celebrities have seen their marriages exposed on the public stage with embarrassing details. Often, the wife not act on any revenge impulses until the spotlight fades and the marriage crumbles.