It'd be like classifying nearly all deaths as caused by "cardiac arrest" even though that's the natural end state of most other causes of death.
I might accept your argument in the small fraction of cases where natural death is not "reasonably foreseeable" (since that requirement was dropped in 2019).
If there’s a concern at the policy level, usually you’d have a separate monitoring system.
Driving policy with population stats is not really the gold standard, in spite of what was communicated to the public during the pandemic. Usually you’d want to run some kind of controlled experiment or very rigorous observational study. That’s where the bulk of the success stories in medicine have come from historically.
For example, imagine that 99% of all the euthanized are people who chose it after a diagnosis of the "Insane Agony Virus."
Obviously we would want all those mortal data-points to get counted as reasons to fight IAV, even if only a tiny number of people died because the virus finally turned their brain to mush after weeks of thrashing about on a table in mind-breaking pain.
Maybe IAV is just a made up term that people use, or far more people believe that they have IAV than is actually the case, or that they are wrongly convinced that IAV is incurable or untreatable, or the medical system has been perversely incentivized to encourage medically assisted suicide in the case of IAV diagnosis, or it's actually the case that it's not IAV causing the agony but actually a prescription drug side effect that interacts with the brain in such a way as to invoke IAV in certain cases, etc etc. None of that is science, of course.
Separately, there should be a list of rationalizations for victims that undergo medically assisted suicide. And it should be analyzed to find ways to reduce the number of suicides.
The correct breakdown depends on goals. If someone is stabbed with a knife, the important cause(s) of death won't be "because a lot of cells couldn't synthesize ATP anymore", and probably not " saying the wrong thing to Stabby McStabberson."
https://www.cdc.gov/nchs/nvss/vsrr/drug-overdose-data.htm
> Drug overdose deaths are identified using underlying cause-of-death codes from the Tenth Revision of ICD (ICD–10): X40–X44 (unintentional), X60–X64 (suicide), X85 (homicide), and Y10–Y14 (undetermined). Drug overdose deaths involving selected drug categories are identified by specific multiple cause-of-death codes. Drug categories presented include: heroin (T40.1); natural opioid analgesics, including morphine and codeine, and semisynthetic opioids, including drugs such as oxycodone, hydrocodone, hydromorphone, and oxymorphone (T40.2); methadone, a synthetic opioid (T40.3); synthetic opioid analgesics other than methadone, including drugs such as fentanyl and tramadol (T40.4); cocaine (T40.5); and psychostimulants with abuse potential, which includes methamphetamine (T43.6). Opioid overdose deaths are identified by the presence of any of the following multiple cause-of-death codes: opium (T40.0); heroin (T40.1); natural opioid analgesics (T40.2); methadone (T40.3); synthetic opioid analgesics other than methadone (T40.4); or other and unspecified narcotics (T40.6). This latter category includes drug overdose deaths where ‘opioid’ is reported without more specific information to assign a more specific ICD–10 code (T40.0–T40.4) (4,5). Among deaths with an underlying cause of drug overdose, the percentage with at least one drug or drug class specified is defined as that with at least one ICD–10 multiple cause-of-death code in the range T36–T50.8. Two additional categories were added based on CDC’s Opioid Overdose Indicator Support Toolkit (6): drug overdose deaths involving natural, semi-synthetic, or synthetic opioids, including methadone (T40.2–T40.4); drug overdose deaths involving natural and semi-synthetic opioids, and methadone (T40.2–T40.3). These new categories, which are a combination of existing categories, are not displayed on the default figure to facilitate ease of display of the main drug categories, but are accessible through the drop-down box that allows for selection of specific drug categories.