I would hope anyone in this hobby cares for the well being of their tank inhabitants. For those who have been in the hobby, many different animals do perfectly well together for certain hobbyists, but may be incompatible for others. Heck, my aiptasia filefish decided LPS were delicious, which is why he is in this tank. He was fine with them for a few months, then decided my elegance coral was the most delicious thing he'd ever seen. He was removed within 15 minutes of me noticing the nipping, and the coral is none the worse for wear. There is a certain amount of risk involved with most aspects of the hobby.
An excellent example of risks reef hobbyists take would be keeping dwarf angels. Many individuals will not keep them in reefs, due to the potential for them to nip corals, or will not keep more than 1 in a system, because they read something on the internet that told them those angels would kill each other. Many other individuals have no issues doing either of these things.
My old 110 gallon reef (torn down because the stand broke) had 5 dwarf angels all living together without issue and with a variety of corals. My current 47 gallon reef has both a rusty angel and a coral beauty angel, in with a wide variety of corals, even some LPS (there is a 12"x8" elegance coral in that particular reef). If there are any issues, I am happy to relocate fish to other systems if necessary, but some other aquarists are unwilling to do so, which becomes an issue.
Keeping more than 2 clowns in the same tank is another excellent example. Most of the time it simply doesn't work, but occasionally it works just fine. My brown saddleback clown pair and my orange skunk clown pair share this tank together without issues, regularly swimming through each other's little nesting areas. Both pair are spawning, and lay eggs every few weeks, but don't give each other a second glance unless they're within a few inches of the eggs. Those two species of clowns are different enough that they don't seem to mind being together, but again, I have the ability to separate them if necessary.
Unfortunately, the my way or the highway attitude many keepers take on this forum drives away many hobbyists. The negativity is rude, depressing, and not necessary. As hobbyists, we should be encouraging, give our honest opinions, and work toward improving the hobby. Reef2Reef is a place where hobbyists should be able to come and ask questions without smart-alec comments. While it won't drive me away, as I love this amazing forum and the many wonderful supportive people on here dedicated to making it a supportive and welcoming environment, the negativity presented here does drive away potential hobbyists or hobbyists struggling with their tanks at home, and may even be the straw that breaks the camel's back and make them leave the hobby entirely.