This is a common argument but it's based on the incorrect assumption that existing difference must dictate the way we shape and envision a future society. It's based on the naturalistic fallacy and is also historically blind.
If you look at history of mankind, you will see that at any stage the existing differences seemed insurmountable and later nevertheless changed. You can look anywhere from the Roman empire (i.e., essentially a fascist militaristic society for a long time), over women's rights, slavery, colonialization etc., it's always the same pattern. The status quo has never defined how a desirable society should look like. As a typical example, many women used to agree that it's pointless for them to vote, since they don't know anything about politics. Maybe these were even in the majority at some time. Nevertheless they've changed their mind.
To cut a long story short, history is full of alleged anthropological constants that were used to justify inequality and all of them turned out to be false and nonexistent. Heck, landowners used to say about peasants that they are just too stupid to own their own land and would immediately gamble it away...
If you look at history of mankind, you will see that at any stage the existing differences seemed insurmountable and later nevertheless changed. You can look anywhere from the Roman empire (i.e., essentially a fascist militaristic society for a long time), over women's rights, slavery, colonialization etc., it's always the same pattern. The status quo has never defined how a desirable society should look like. As a typical example, many women used to agree that it's pointless for them to vote, since they don't know anything about politics. Maybe these were even in the majority at some time. Nevertheless they've changed their mind.
To cut a long story short, history is full of alleged anthropological constants that were used to justify inequality and all of them turned out to be false and nonexistent. Heck, landowners used to say about peasants that they are just too stupid to own their own land and would immediately gamble it away...