It sucks as a whole. Imagine having everyone's DNA. You can develop things that hurt a specific set of people only. It may or may not affect you directly, but it affects our communities. You're right as an individual. No one really cares about your hair or spit and if they did, it's very easy to get a hair sample in most cases without you even knowing it. As technology gets better there will be (maybe already are ways) to get your DNA that are less intrusive or need less material. AI trained on DNA and physical attribute could probably narrow it down A LOT using video alone.