The idea of "morality" is very black and white. Something is either moral or it's not.
I fall into the camp, possibly because I am religious but I've viewed it like this even when I was atheist (yeah, wrap your head around that logic), that morality is definitely something that's objective. It's just
situational. In my brain the idea that there
is a right answer, or at least a "least wrong" or "least worst" answer, is something that's been with me for ages. But as I've gotten older and come to see that in reality life doesn't have a lot of actual existential meaning, and that we choose what we value, the fact still exists that everyone's moral code is going to be different.
Personally, I just say that their morals are either right or wrong, and cast myself as the arbiter of morality (because why not? It doesn't mean anything anyway, this is my circus
and my monkeys). When it comes to boundaries, they can't be moral because it's not immoral to enforce a boundary since it doesn't harm anyone to do so. They can only be reasonable and unreasonable (which lowers the amount of people you can agree to interact with).
In some ways I agree with
@EveHarrington, and this is something I saw often when I was on the scene. That people would reach out to me and want me to hurt them and it was clear they were working through trauma that they hadn't dealt with, and were attempting to use BDSM as a tool to do that. I was not comfortable with harming anyone, so I rejected them.
Thus I made the decision for them not to engage and removed their agency from the equation (partially because my boundaries superseded it and partially because I viewed it as morally wrong). But on the other hand, does a person actually have the agency to make these decisions? I think on some level they must, even when it comes to death, because people should have the agency to be able to kill themselves if they choose.
(But of course, doing this at the hands of someone else, I would say is morally wrong, because both of the parties involved are failing to understand the consequences of actually taking a life, regardless of if "consent" is given, and especially if the person was healthy prior to this. But let's say the person wanting to die had a terminal illness? Then it's morally correct for them to receive medical assistance in dying, if they so choose, yeah? And usually that's at the hands of a medical doctor, or these days it can actually be self-administered.)
So there's a lot of nuance even within "objective" morality.