to an extent, the right is making a point - these are frequently not cases where somebody needs a doctor to administer the suicide, but situations where the expression of free will should be done autonomously. self-ownership means you have the right to kill yourself, and the right to ask others to do it for you if you can't, but the focus should be on doing it yourself.
i might concede that assisted suicide be restricted to scenarios where the individual is unable to do it themselves. if you really wanted to die, and you could, you wouldn't call a doctor and wait for it, you'd just do it. in some cases, the hesitation might be instructive.