That's a fair point. And in a sense, the analogous law there is the right to medically-assisted sterilisation, which also exists (albeit, carrying a somewhat lesser impact in terms of finality).
I don't necessarily think a discussion down that line is entirely without merit, and one could of course "delve" into philosophy of benefits to society vs rights of the individual vs sanctity of life etc ... but this is not the main point I was making here.
For me the distinction is less about reproduction-aversion versus suicidality needing to be forcefully "cured" or not (or one of sanctity of life, for that matter), but more about one of capacity in the case of exercising reproductive rights as compared to exercising suicidal rights. At the risk of a bad analogy, the former is more like wanting a questionable piercing that others may think is a bad decision. Yes you may well also regret it as a bad decision eventually, but if you have capacity in your decision at the time, then there is little reason to stop you from exercising your right to self-mutilation if this is what you want. In which case, yes, if someone was claiming, either that "skin is sacred", or using circular logic that the very fact you want a mutilation proves you're sick and you need to be 'cured' of it, I would have had the same response as you.
Whereas there are good reasons there are lots of legal protections for proving or disproving capacity when dealing with people with dementia signing away their will to a total stranger, for instance. Yes, it's possible that the demented person still has enough cognitive capacity to sign away their will to a total stranger, despite the fact that cognitive capacity is the very thing that is compromised. And so, similarly, yes it's possible that the suicidal person still has enough capacity to judge the extent to which they wish to live, even though their ability to wish to live is the very thing that has been compromised. But I would be sceptical, and would want to see some guardrails before providing commercial services to help demented people exercise their peaceful right to sign away their wills. And we have enough medical knowledge currently to know that, capacity-wise, suicidality is much more like dementia in this context, than it is like wanting a bad piercing or deciding on reproductive rights.
Which is why it's rather frustrating to watch, and a very dangerous line to walk, when legislating such a provision away purely on the basis of a debate focusing on "personal rights vs sanctity of life", without having that discussion about capacity and obligations to attempt to restore it / protect it as the first priority.