Sort of came up at the beginning of Morrison's Batman run too when Bruce points out that engaging the type of bad guys they face on a regular basis without having those encounters result in any fatalities requires a ridiculous amount of precision and self-control.

Although, the inverse argument was made, in Kelly and Mankhe's "JLA: Obsidian Age", since the League of Ancient's willingness to kill and cause collateral damage was cited as the edge they needed to beat and kill the JLA.