Does it matter whether the state executes a criminal who has the mental capacity of a ten- year- old?

Does it matter whether the state executes a criminal who has the mental capacity of a ten- year- old? Does it matter who actually writes the term paper you turn in and represent as your own? Does it matter whether we can easily save a drowning child but casually decide not to? Does it matter whether young girls in Africa undergo painful genital mutilation for reasons of custom or religion? Do these actions and a million others just as controversial matter at all?