This epitomizes the problem with fresh-out-of-school "founders" who view their startup as some sort of a post-grad experience. The guy mentally still is in a high school, but is supposed to be a responsible adult running a company. Every businessman has challenges running their business, but not every challenge is something that has to be known publicly. Business is supposed to be ran from the quiet office, not from the confessional booth.
If I would be an investor in this guy's company, I'd be really pissed off.
No one so self-aware that they can openly discuss their shortcomings and their fears is "mentally still in high school".
Discussing them openly does have consequences, though. Especially for those following you who may not see it in the same light. As shown in the comments of this thread many are vicious against it and see it as weakness. In my experience, though, those who do share the same frame of mind as the OP (Many of whom are very successful leaders) see it as a strength.
So I partially agree in that perhaps it's wise to keep it to close confidants I disagree that this is something that needs to be rallied against.
It's lonely at the top in a startup. Figuring out where to go can destroy you if you let it. It's like guiding a ship through a thick fog (The doubt) and the only thing getting you through it is the lighthouse (Your determination to never give up and belief in the idea) and the skills you've developed to steer the ship away from the rocks to get to the lighthouse. I'd doubt anyone's ability to get through that if they weren't unsure and constantly questioning themselves. Over-confidence is the killer of great performance.
The product is great. All is else is secondary. For christ's sake the guy has Zach Klein on speed dial, they'll figure things out.
As as Svpply user, this only makes me want to root for them more. But to be fair, if I were a Svpply employee, my confidence in his vision of the company might waver a tiny bit.
If I would be an investor in this guy's company, I'd be really pissed off.