As for what people find easy to separate in their own minds that's down to the individual. I'm sure members of Al Qaeda believe they have the right to kill people as much as the USA believes they have the right to the death penalty. But ask the same question of Amnesty International and they might disagree.

If you support the death penalty then surely the decent have a right to die with dignity and if don't support euthanasia the guilty should have the right to live?