I presume that those who feel that green is an unlucky colour do not walk on grass or have a lawn, don’t walk in a wood, don’t have any houseplants or flowers (green stems and leaves on them), don’t own a green parrot or budgie, etc, etc. 😊.
I’m really mystified as to the reasoning behind thinking a colour is unlucky in some way, just as I’m mystified by other superstitions such as ones about various precious stones being unlucky, (eg opals and pearls), having to greet a magpie if you see one, to avoid bad luck, not walking under ladders, not putting shoes on a table, not opening an umbrella indoors, etc, etc. Where do these notions come from?
I know some superstitions stem from events long past, but others seem to bear no relevance to anything that makes any sense ( at least, not to me they don’t).