If you ask people, how many of you support raping people who rape, you would find it very hard to find anyone that would support that... The reason why we would be hesitant to endorse it is that – what normal person would be paid to do something so compromising as raping a human being? But yet we have this idea that we can kill someone in a way that doesn’t implicate us. If it’s not right to torture someone for torture, abuse someone for abuse, rape someone for rape, then how can we think we can kill someone for killing?First of all, don't bet you won't get volunteers for the raping-rapists thing. This isn't the country it used to be.
Second, the answer to your question is that rape is always wrong, whereas killing is sometimes right and praiseworthy. I'm good with being "implicated" in something honorable and worthy of praise. The problem isn't killing, it's the structure of executions. What's wrong with the execution is that there's no honor in it, because there's no risk in it. It's like taking out the garbage. Sometimes you have to, but that doesn't make it glorious.