[Rant] Defended a dino I was trying to tame, then my dinos walk over and kill it. WTF

So they were on passive while I was knocking out my new dino, everything was going well. I then turned them back on to neutral to help me fend off other carnivores. They were getting too close so I turned them back to passive so I could finish off the offenders. That went well, then whistled for them to be neutral and they decided to suddenly kill the dino I was taming. (it never actually hit me or them) Why? And what the actual fuck was that? So annoying.