You might notice one modality in the folks who support Terri's offing -- they are self-driven control freaks. They demand complete control of all their choices and happenings of life.
Having the responsibility of caring for a person long-term -- to give up so much of one's life to do so -- seems impossible to them, so scary, that they treasure the "bring me the dynamite" options of life, where such are available. Like in offing the bedridden, the addled, the cranky and crazy, the sickly, the barely-responsive burdens. That's just one modality --- there are others as well, other reasons why people side with the "loving" husband.
And that lover-boy? What is his motive? Very strange, imo.
When I was pregnant with my second child, the doctor asked if I wanted to have a test taken, to see if there was something wrong with it. I asked why would I want to do that? He said, in case there was, I could know and decide whether or not to terminate the pregnancy. I said, I would not take that test; I would not terminate the pregnancy. I do not want to know anything, because then I'd be putting my faith in doctors' tests and not God's Will. If I had a handicapped child, mentally or physically, then God would help me take care of that child. And in the meantime, I could still pray that I would have a healthy child. The doctor looked at me like I was crazy. My child was born healthy. I thank God for that, but I know if my child had problems, He'd help me, and my child through those. All life is valuable and created by God.
I think you are exactly right. It is a shame in this modern world, people so easily feel they are burdens, and other people are so quick to see that way.