I think maybe you're misunderstanding the whole ancient greek thing. You keep saying that since they had only one word for blue and green that they 'saw them the same', but that doesnt at all mean that their brains processed the input of blue and green colors identically. I mean just look at how we define colours. What exact shade is red? Theres hundreds or thousands of different colours that would all fit into most people's definition of 'red' and that likely differs from person to person. Just because the greeks referred to different shades of blue and green with the same overarching word, doesnt mean they couldnt distinguish the difference at all. Calling multiple shades of a color a single namr doesn't prevent us from seeing the differences between those shades which seems to be what you're inferring.