It *is* relief. You seem to have some misapprehensions about me. Allow me to enlighten you: my first scar is on my wrist. I was eight. Suicide is all about leaving behind the pain of life. It's all about ending the pain and suffering and hopelessness. So, yes, it *is* entirely about relief.
For you it's about relief, based on your experience. That doesn't mean your experience translates across the general population. I've worked professionally with many people over the years for whom suicide has been a current, constant consideration. It's also been an issue for me at times.
What I know is that there are as many drivers towards suicide as there are people, as many understandings and meanings for people wanting to, or feeling uncontrollably driven to, end their life. Sometimes looking for some kind of relief, sometimes wanting everything to stop, sometimes feeling like they had indeed "completed" the useful part of their life.
What I see here is you struggling to comprehend that anyone in that place has a different experience of it than you did, therefore you're best placed to decide the language used to talk about suicide.
I do use "completed suicide" in my discussions with fellow professionals. We all know what we're talking about and common language is essential in my work.
In my work with people for whom suicide is an issue, it's all about them, their framework, their use of language, their experience - the connection and relationship is way more important than the words used so I'll go with what works for them, checking that we're on the same page if need be. Some will talk about attempted/completed suicide, some talk about ending their life, some talk about committing suicide - it all boils down to someone in excruciating pain, and it's important that I get that.
I don't think "complete" is always a positive thing, nor do I think - in the midst of incredible pain - me saying "completed" instead of "committed" will make a blind bit of difference in terms of someone's decision making process. Frankly if they're at the point where they can logically reason "complete is a good thing therefore suicide is good, I think I'll try that", they're quite far from crisis point and there's other work I can do with them.
Where it can make a difference is with those who are left behind, but again using their words, their frame of reference in their own time cuts across the semantics quite a bit. But amongst professionals common language is a good thing, and in that clinical setting I use "completed".