What surprises me isn't that AI failed, what surprises me is that Zuckerberg believes in his own hyping of AI so much he had the confidence to try to do this at all, live, unstaged. Is this courage, honesty, stupidity, hubris?
The most favourable explanation I can think of is that they tried it out ahead of the presentation, it worked well enough, so they trusted it could be repeated.

How the fuck is this even legal?