As many here I wholeheartedly disagree with the argument made by the article. It might be one of many reasons but not the main one.

Another argumemt against the death sentence I haven't heard here:

I think the whole 'eye-for-an-eye'-principle of the justice system sets a negative example for the respective society and thus facilitates violence.

"It is okay to kill someone for a crime. Even the state does it. My reason is valid."

It lowers the bar for violence even further unnecessarily.

I did not fact check this. Its just a gut feeling.