Diana, keep in mind that many warnings are given with good intent. I was warned that keeping purple anthias was near impossible. I'm an experienced aquarist with the ability to attempt meeting needs of anything they need. I got 4 dead anthias out of that test. so when someone says that "generally" something will die, it doesnt mean always, it means often enough to not risk killing something. If you're going to do it anyway, and it works, great. If it doesnt work, well, lesson learned, and don't try those again.
So if someone says they want to try a butterfly that 99 out of a 100 die, I think the warnings are warranted. Often the warnings come from those that have previously killed those very fish. I know if you post about wanting purple anthias, I'd warn against it.
Now we hope that the warnings come in a tempered tone, but as you know, people are passionate about things, and that often comes through in a bad tone.
I recall a facebook friend going on about a mistreated rottie, she was very passionate and you could see that in the tone
Remember, any negative comments are not because people don't like the poster, it's because they love the fish. Yes, they should maybe re-read then count to 10 before hitting submit, but that's in a perfect world.
we were all new once, and we all killed things we we're warned to not attempt, and mostly we try to save others from that sad situation.