nisht: Removing a ventilator? Maybe. Removing a feeding tube? There is no way that that can be called Retzichah.
Again, I’m agreeing that lots of people can be Over and even Issurim Chamurim when they deny/don’t know Halachah. But being mistaken about Halachah is different than doing evil things. (Especially when there are some, albeit a tiny number, of Halachic authorities who held that brain death is considered death.)