No, they're asking for a negative to be claimed not a negative to be proven.
"Can you explicitly *state* that..."
"State" meaning to say or write a claim, no proof involved.
One could argue they are baiting OP to make a concise statement about Facebook policies. I wouldn’t touch that with 10 foot pole.
Strange, a concise statement about Facebook policies with a LOT of internal information is precisely what this blog is.
Perhaps you should read the blog first?
In order to state anything which they know to be true, they must first prove it to themselves. But if it is something which cannot be proven, then of course they cannot know it to be true, and consequently they cannot then honestly state it.