You'll find a wide spectrum of beliefs within that "same breath".

Personally, I think life in prison is necessary in some cases - that there are people who will never be able to function safely in society - but that it is simultaneously overused (case in point: stealing four cookies; https://www.latimes.com/archives/la-xpm-2001-jun-19-me-12244...).

There's also the "you can release someone from life in prison" aspect if there was a mistake, malicious prosecution, or they've shown signs of genuine rehabilitation.

My opposition to the DP is based on my distrust in our justice system and the fact that a wrongly applied DP is irrevocable. Life w/o Parole lets you amend failures in our legal system.

It's a common opinion. I find this stance a bit weak, since it doesn't hold the justice system to the highest standards and expectations. I know, death seems so immediate and there is no taking it back, but things aren't usually that trivial in reality, a life in prison can also mean the person dies in prison without reparation, or even if revoked, the person might spend most their life in prison and has a few years to live free. A person on death row might have many years to prove their innocence. I guess we could also apply a statistical analysis and determine if the error margin is tolerable, sort like how we handle hundreds of deaths in traffic.