In objective reality we are all sharing the same physical world, thus our actions affect other real beings, laying some grounds for morality, at the very least the "do onto others" and its invert.
But if reality is subjective, and purely a construct of a central to it consciousness with no common objective physical manifestation, that appears to render morality obsolete.
For example, in the context of murder:
if I am central and define this reality, then murder will be a crime against a figment of my imagination, and therefore will not matter
if I am a product of someone else's reality, I am just a figment of that consciousness' imagination, therefore I don't have control over my actions and bear no responsibility for murdering anyone, including the central person
solipsism or not, even if "the extras" are real people, my actions will only affect them in my reality, and not in theirs, so no violation against another consciousness takes place, and a violation against someone else can only take place if they themselves manifest it in their subjective reality
So how and why would one have morality in a subjective reality?