Indeed, perhaps he just likes marshmallows.
"Must mean that we're trying to hide the fact that we funded them, right? It could only mean that."
Could be
A) sarcastic cover while distracting readers from the fact that there's no good reason (trying to get others to appeal to authority)
B) there's a real reason which is sufficiently obvious that someone jumping to conspiracy is off-kilter
If (B) were the situation, the "real reason" isn't obvious to me or to the parent (and I suspect you don't find it obvious either)
The question of our times, by the way, is answerable with the search box at the bottom of the page.
But for the record, just go look for all the stories about YC companies that aren't labelled with "YCxxx".