It might be a difficult problem to solve, but there’s no evidence that Facebook is working on it or that they ever intended to work on it.
The easiest explanation is that Zuckerberg was lying. We could give him the benefit of the doubt but since he’s always lying it makes more sense to save time and assume he’s lying about this as well.
Based on your use of the word always to describe Zuckerberg as a liar, I infer that you are upset by FB, understandably. I would add that I am not a fan of FB and I am deactivated, but unless you work at FB, making comments on if they are working on it or not is just speculation. I would say a more probable speculation is >=1 employee is working on this tool.
The easiest explanation is that Zuckerberg was lying. We could give him the benefit of the doubt but since he’s always lying it makes more sense to save time and assume he’s lying about this as well.