It is done for so-called humanitarian reasons, economic, or for purifying the gene pool, or political reasons. Hitler used these reasons for genocide. Abortion comes under this category. The first is the least controversial. Some do not even classify it as a form of Euthanasia.
Death is still inevitable.
There comes a time when further medical assistance is pointless. In the case of involuntary Passive euthanasia the patient may not be able to decide due to a coma. Problem for medical personnel is miraculous recoveries on record, e.g. the boy in a coma for 10 years, suddenly comes out it. Involuntary Active euthanasia is practiced today in this country in the form of abortion. In the Netherlands and some other countries it is being practiced on the elderly.