If memory serves, Viguerie has opposed the death penalty at least since the 1980s out of fear that an innocent might be executed by mistake.
That is a legitimate concern. A court that executes someone wrongly is itself guilty of murder, a capital offense.
According to Noachide Halakhah only an eyewitness can convict someone of a capital offense. Hearsay, circumstantial evidence, and even confessions are not sufficient. Also, non-Jews are permitted only one means of execution: "by the sword" (which means beheading, though hanging will do). So we're definitely not doing it right.
I was simply concerned that he might be opposed to the death penalty in principal, even when execution is called for.