I'm not in the target demographic for products like Soylent. But someone in my social circle sells AdvoCare and others within that circle eat it up. Soylent is entering a market at least as accepted and established as the technologies mentioned in your comment.
Your logic can be applied in regard to the consequences of a whole host of technology ideas which involve personalizing user experience, providing relevant advertizing content or analyzing user behavior.
As a parent, I certainly wonder about the long-term consequences of online behavior, and expect they are of a far more irreversible nature.
If you make a new A/B testing tool or a spiffy way to choose colours for a website nobody is going to wonder what the long term health consequences might be.