I think its the implication. When you were planning on returning to work, before you knew you'd have a child who was ill, you probably resented those people who suggested you stay home. Its sort of patronizing to assume someone is not aware that they have that choice - in theory (the reality is that for a lot of people, they don't have choices - they have to work - and often have substandard child care arrangements or are dependent on family. Or they have to stay home because there is no option for even substandard child care or family). We all know we have a choice and most of us know how lucky we are to have it.
If someone comes on here and says "hey, I'm going to Disney for my vacation, how should I save" and someone comes back with "oh, just don't go" that would be sort of rude. But that's what was done in this case.
I was home for a year when my son was in 9th grade. I homeschooled him - which was the best choice for us at the time. But I wouldn't say to anyone who was sending their kids off to school "oh, you should homeschool" I'm happy to talk about how I did it and what it was like if the conversation turns to homeschooling - it had pros and cons and ups and downs. And if someone were to talk about their kid and it sounded a lot like our situation, I might say "yeah, we went through that, we homeschooled for a year." (There is an exceptional amount of privilege in being able to homeschool your kids - especially at a high school age)
And my problem isn't with "you should stay home" but "you should stay home because it will save you money" - when the assumptions people make in order to make that work out are often loaded to make staying home more financially attractive than it is.