Green dye crafted from yellow and blue dye

I’m sure this has been mentioned before, but I’m new here. I don’t get why green dye can’t be crafted from blue and yellow dye. I might be wrong but I think it’s the only non-primary colour in the game (other than black, brown and white) that can’t be crafted from other colours. Given how slow cacti grow it seems ridiculous that’s the only way to obtain it.