There are certainly better testaments to humanity than morals, as they are enherently subjective. And asserting reality as the benchmark to guage those morals is pointless, again subjective, and by that measure, everyone is right, and yet, we know otherwise

Morality (or ethics, if you want to phrase it that way) does not seem to be that subjective. For example, the vast majority of people solve the Trolley Problem [en.wikipedia.org] and similar dilemmas the same way. People seem to instinctively feel that it's "right" to save the most people possible, if it's not possible to save everyone; that it's an obligation to take action to save innocent lives; and that it's wrong to put innocents in harm's way, to name a few such scenarios.

It's only when politics and religion enter the debate that people start changing their answers. Politics and religion tend to dehumanize persons, so that the answers suddenly depend on what nationality or faith or sect or even what political party the innocent lives belong to. Sometimes even following the wrong football team is enough to do it. Jewish schoolchildren questioned deplored a massacre conducted by a fictional Chinese warlord, but approved the same massacre under the same conditions when conducted by an Old Testament figure. Why? Because their religion entered into the equation.

So one could argue that we have a biological, evolutionary sense of right and wrong, evolved due to the socialized nature of our species. The Golden Rule is something we understand inherently, because our brains are programmed for give and take, cooperation, barter, and helping one another, since this helps our gene pool. But religion and politics (which often motivates the same emotional responses as religion) corrupt this programming and influence us to see others as "outside" the tribe, not worthy of our help, not worthy of living; not fully human, in fact. Witness the nicknames given to enemies in wars throughout history. It's easy to hate "gooks, huns," etc... but if you see them as individuals like yourself, it becomes harder to kill them. That's why armies spend so much time training soldiers to kill on command and not think those exact thoughts.

Ask the theist to prove his morals are objective. Even their god has subjective morals.

Agree. There's no such thing as objectively true morals. Mortality is a social construct and demostrably changes over time and differs between societies.