Because traditionally both of those recipes are not vegan? Chili is meat based and pumpkin bread has eggs. You didn’t make chili and pumpkin bread, you changed the recipes. They feel the need to indicate that somehow.
I don’t know your family, so I don’t know if they’re doing it to be annoying, I guess if they’re also calling your salads vegan salads, that would answer the question, but I don’t see any harm in them labeling the vegan food you make as vegan food. They still eat it right? They’re not shit talking it for being vegan are they?
“Chili” is a pepper. Chili con carne is the traditional dish. There’s no dish called “chili”. The version without meat is an adaptation that came later.