I've enjoyed the OPs responses, just read through them all. She sounds very down to earth and reality based. I personally was ok with a bit doing a bit of care for older relatives when it was thrust upon me, but you are absolutely right, you are not morally or ethically bound in any way to do so.
What I do find extraordinary is the way the martyrs always flock to these threads in a desperate attempt to shame and blow their own trumpets.
It's as though they are simply incapable of understanding that their point of view is not everyone's, not even the majority necessarily and cannot bear that reality.
The OP asked how it went if you refused to care for older relatives and we've got 37 pages of martyrs and saints admonishing her. 😂
The worst thing is that many of these sainted people are not actually caring for their relatives, they are paying someone else to do so. Now, that is absolutely fine by me - but you don't get to lecture anybody on caring when all you do is pay someone else to do it. Well, I mean you do, obviously, but you sound like a hypocrite.
Actually, worse than that was a funeral I attended on a livestream just recently where one of the sisters in law made it the all about her show. She got up to speak and endlessly wittered on and on and on and on and made sure to mention in passing several times how fantastic she personally was having taken on the tasks of old age care. He was in a home, mind you, but she was definitely the saint. Her husband also gave her kudos for her choices. Actually pissed me right off, the man they were discussing had been in good health until he declined sharply after a fall in his late 80s, he was a very dignified man and would have been utterly horrified to know people had mentioned wiping his arse at his funeral.
We all make choices. I have a friend whose mother breaks into his home (she does have a key when I say breaks in she uses it against his wishes) every year and puts a nativity scene up in his living room, even though she knows he's not religious. This has been going on for decades. He claimed he couldn't stop her. I pointed out he could change the locks. He immediately became super defensive and went into a long and boring list of reasons why that would be a bad idea.
Bottom line, he didn't want to deal with her tantrums, so he was putting up with it.
That's fine, entirely his choice. If yours is to be a martyr, go for it. I can see that not getting recognition for that martyrdom has turned some of you into scolds with little understanding of other people's needs and feelings and several of you are behaving like downright c**ts for all your claims of being nice and loving people.
Meh, who cares, really, just a few thoughts.
Anyway, good on you for being so firm on it OP, as can be seen you will face a mountain of opposition from a vocal minority and it's best to be prepared in advance.