Individual "carers" mass murdering disabled, incapacitated, and/or elderly people has been a thing that sometimes happens for as long as I can remember and, yes, I think it is an extension of cultural memes about involuntary "euthanasia" for people whose lives are deemed to be worth-less/worthless by mainstream opinion.

Clue: if it's involuntary then it's not "euthanasia".

Clue: there are many good reasons why most cultures have deeply embedded memes against suicide aka "voluntary euthanasia".

I'm not against all suicide, or living wills in which people preemptively decide to choose not to be resuscitated in extreme circumstances, but many of the examples I'm seeing used as arguments in favour of "voluntary euthanasia" look to me more like people who need better care and/or treatment before they make any life-changing decisions.