How was Alexander sentencing people to death a good thing?

In this chapter Alexander is mentioned. It is said that he needed to kill people to show that he was a strong leader who gave sober judgment to each person he put to death. Apparently he needed to do this because people thought he was "sissy boy" ruled by his mother. Check this out,

"But let us come to Alexander, who was a man of such great goodness, that among the other praises which are accorded him is this, that in the fourteen years he held the empire no one was ever put to death by him unjudged; nevertheless, being considered effeminate and a man who allowed himself to be governed by his mother, he became despised, the army conspired against him, and murdered him."