That’s a tremendously sticky topic. Real tar baby.
What you posit I would call more of a libertarian position than a right/left position, and I personally view libertarians as outside the left-right paradigm.
This ‘rights based’ opinion is probably defensible, conceptually, but I don’t think it holds for many suicides, especially firearm related ones, because it presumes the person is acting rationally. If a sane, well reasoned person comes to an informed and logical conclusion to kill themselves, I think a case could be made that they should have the right to do so. But I also strongly suspect that most suicides are not by sane, well reasoned people who’ve reached the act from an informed, logical process.
I don’t have a data driven opinion on this, unfortunately, just suspicions and anecdotes. I have known two people in my life who committed suicide, both by firearm. One was a teenager, and the act was the result of a romantic entanglement. The other was an adult who was under a vast cocktail of antidepressant medications, and underwent a change in her psychiatric drug prescription. I can only speculate, but I believe both would be alive today if they were able to get beyond the suicidal thoughts themselves, which I believe in many cases to be fleeting. That said, I’m not a professional.
Honestly, when I was researching this, I thought adolescent suicide would have been a much higher number. I had no idea it was so tremendously weighted towards responsible adulthood until I saw the statistics.