@reasoning logic,
One sided 'opinion.' If subjective is only something that takes place in a person's mind, that then contradicts everything that they call objective.
Humans define everything by what we see and experience. There are some things humans "see" that are objective, but not based on more than objects. When we say, "the sun will rise tomorrow," that's an observation that is objective; there is nobody who can deny that fact. It's based on human observation and interpretation. When one human kills another, that person is certainly dead; that's objective.
Where it becomes subjective is the reason(s) why one person killed another.
Morals are subjective to a certain degree, but outright killing, stealing, hurting others without cause or reason, are objective. There are standards of morals that are universal which doesn't depend on culture, politics, religion, or ethnicity; they are objective.
With most moral issues which many claim is subjective has to do with whether the victim is yourself, a family member, or a loved one. If they are killed, raped, brutalized, stolen from, or any number of violence against them, it's objective. If those same crimes are perpetrated against others and strangers, it can be subjective.
The killing of six million Jews by the Nazis were immoral, and an
objective conclusion by any universal standard of morality.