Yes, all those things kill people but the difference with AD is that it's the deliberate ending of life by the state. This means that Article 2 rights are engaged:
ARTICLE 2
Right to life
1. Everyone’s right to life shall be protected by law. No one shall be deprived of his life intentionally save in the execution of a sentence of a court following his conviction of a crime for which this penalty is provided by law.
2. Deprivation of life shall not be regarded as inflicted in contravention of this Article when it results from the use of force which is no more than absolutely necessary:
(a) in defence of any person from unlawful violence;
(b) in order to effect a lawful arrest or to prevent the escape of a person lawfully detained;
(c) in action lawfully taken for the purpose of quelling a riot or insurrection.
https://www.echr.coe.int/documents/d/echr/convention_ENG
If we could guarantee that every person was making a fully informed free decision, free of coercion and free of the fear that the only alternative was substandard care, then fair enough, nobody would complain about their/their loved one's right to life.
But we can't guarantee that because safeguarding is never perfect and is frequently a very long way from perfect. And so much care is substandard that that would be a reasonable fear for a lot of people.
Some number of people will have their lives intentionally ended by the state when they did not want to die and every time that happens it will be a major human rights breach. That's why it's different from your examples.
Aside from the exceptions in paragraph 2, Article 2 is an 'absolute' right which means there should be no argument about proportionality, i.e. 'It's acceptable for a few people to be deprived of their lives intentionally, when they did not want to die, in order to relieve the suffering of a much larger number of people.'
But we're beyond that now, aren't we? People are making exactly that argument. I'd like them to put some numbers to their argument so we all know where we stand.