All we know is that this one guy has survived on it for months. How will his health be after 5 years? 10 years? Both if he stops now and if he continues. Nobody knows.
And that assumes that everyone is the same as this guy.
"Nobody knows" and "interesting to see" are very different to the claims made by Soylent:
"You can finally join the easy, healthy, and affordable future of nutrition."
"What if you never had to worry about food again?"
"For anyone that struggles with allergies, heartburn, acid reflux or digestion, has trouble controlling weight or cholesterol, or simply doesn't have the means to eat well, soylent is for you." (this one is clearly making medical claims and I am amazed that Soylent avoided regulators)
"Soylent frees you from the time and money spent shopping, cooking and cleaning, puts you in excellent health,"
"there is much evidence that it is considerably healthier than a typical diet."
People can do what they like with their bodies but the Soylent founders were shady by making these nonsense claims during fundraising.
Sure, but ceasarby didn't raise issues about Soylent's claims, s/he wrote "You can't live on just Soylent either.", and that's the post being replied to.
You claim that Soylent is a fun experiment. Soylent don't. Soylent claim that you can replace all your food with this forever.
When someone says "you can't live off Soylent" and someone replies that it's a fun experiment letting people know the lies and misrepresentations from the producers of Soylent is a valid response. Soylent is not being marketed as an experimental product woth some risk. Soylent is being marketed as a finished product that has health benefits.
I do understand. That just wasn't what was under discussion here. The back-and-forth was about the possibility of living on Soylent-the-product, not about the claims of the company.
I'm not declaring it impossible, but I think that saying "this is a meal replacement, its safe to replace all your meals with it" is premature and potentially dangerous.
And that assumes that everyone is the same as this guy.