Your “lonely people giving up on life” is a huge reach. It’s just food. People are capable of socializing outside of meals.
Setting that aside for a moment, though, you also don’t have to replace every meal, as is mentioned elsewhere in the comments. How about just breakfast? Despite it being greatly beneficial to start the day with food, many people feel like they don’t have the time. Something quick, filling, and taking no preparation is ideal.
"Powerfood" additives, being basically an orthogonal component -- aside, it's basically a powdered (or perhaps pasteurized concentrate, a la Minute Made) remake of the classic, fresh-everything version of your regular breakfast smoothie.
You don't see any issues with that?
The hackles come up when it's promoted or discussed as a broader meal replacement.
Which just so happens to be Soylent's business plan.
But yes. Their broader business plan and certainly what gets the press seems to be Soylent as broader meal replacement. If this were just another "nutritional drink on the go" absolutely no one would care.
Food is life. If you've replaced food with some manufactured shake, it just seems fundamentally wrong. Meals aren't obligations, they are when people get together. They're a time to reflect and experience life. WTF are you doing that eating dinner is too much of a burden?
I can see using something like Soylent as a backup for fueling up while traveling or leaving it at your desk or in the car for a pinch situation. Full on food replacement conjures up images of lonely, single people giving up on life.