Think of it like dithering. Not all of us could afford full 24 bit color displays and had to make do with 256 or 16 colors or 8 colors instead. Sometimes the right color brick isn't there and it's better to have the odd colors spread throughout the whole thing than one brick that's off.

I lived near a Samsonite factory (they manufactured Lego in Canada) and my bricks were purchased in giant shopping bags. They were all seconds which means some parts had color problems, some were a bit melted, some were cracked, etc... Mostly they were fine and I had a lot of bricks.

I know! I remember as a child spending forever digging through the Lego pile looking for the right color. I had to reluctantly teach myself that it was okay to build with any color first and then go back and swap out with matching colors afterwards once I was happy with my design.

Bad analogy: If you dipped your brush in the pot and it came out a random one of a small selection of colours, would you wash it off until you got the "right" colour when the only requirement was to put paint on the paper?

Do you build with lego by picking random pieces and sticking them together? If you are choosing the next piece by shape, why not add color to the selection criteria?

Not random, but functional equivalence is fine.

I always cared about how it looked too.