Those sorts of baseless assertions are not abstract or anything, they're arbitrary. The reason they often come up with murder, theft etc. is because those are prerequisites for a functional society (and, equally, moral since morality obviously conforms to reality). The problem with your position is that morality is arbitrary and indefensible and comes down to nothing but whatever most people believe (and thus has the most force behind it) is moral, thus the Inquisition was just as 'just' as theft and murder. I know what it means to be good, as do most people, because humans have an innate capacity to reason and function socially.
Essentially you do not believe in morality, so I can't debate with you on a non-principle.