If they could, then slavery would be good, right? The question is which is the higher moral value. Which derives its value from the other.
Did liberty have more value for Patrick Henry than survival? Do those who prefer slavery to death have higher or lower values?
It’s impossible for a society to sustain the want to live and to be alive, if it is under slavery, or condones it. Remember again, it’s not about the individual alone. It’s also about the descendants of the individuals, and beyond - the survival of the society that will guarantee the survival of its individuals’ descendants, and therefore, the survival of the society into the future.
A society where individuals submit themselves to slavery, is a doomed society. The violation of the Golden Rule is further encouraged, and eventually results in the destabilisation of such societies - making them non-conducive to thrive in. Would individuals in such societies not want to rise against this, so that they may redeem themselves of the oppression, and in turn, redeem their fellow beings too? Isn’t such a motive an application of the Golden Rule, when tyranny is fought not just for the benefit of the individual alone, but for the rest as well?
There is an interconnect between generations that the Golden Rule is critical in maintaining, that you are choosing to ignore. It’s not about the individual alone. Humans are transient entities - and their offspring is what allows them to maintain a mark into the future - to ‘transcend’ this barrier of finite life. Humans are also social beings, whose lives are critically sustained by the society that they belong to. Damage to either will cause damage to each other.