Your argument only makes sense if you believe you are innocent of all present and future crimes, which is an impossible fact to know by the very fact that you do not know the laws in the future.
Your last sentence is a counter-argument against excuses for surveillance. "The argument 'you have nothing to worry about if you did nothing wrong' means you think you know what laws in the future will be like." It's inappropriate here because we're not talking about surveillance; we're talking about people who willingly gave out their genetic data to some company. The company did not divulge the data, so this discussion is not about privacy and ethics. Maybe don't tell Facebook everything there is to know about you? Maybe don't send genetic samples to whoever to learn random nonsense that doesn't matter about your ancestry? If you do and it leaks, TS?