His article commentary on G+ seems to get more into the "dissing" territory:
Enough thoughtful AI researchers (including Yoshua Bengio, Yann LeCun) have criticized the hype about evil killer robots or "superintelligence," that I hope we can finally lay that argument to rest. This article summarizes why I don't currently spend my time working on preventing AI from turning evil.
See this video at 39:30 for Yann LeCun giving some comments. He said:
Also here is an IEEE interview:
...Spectrum: You’ve already expressed your disagreement with many of the ideas associated with the Singularity movement. I’m interested in your thoughts about its sociology. How do you account for its popularity
http://fusion.net/story/54583/the-case-against-killer-robots-from-a-guy-actually-building-ai/
(An earlier version of this article was titled 'Andrew Ng disses UFAI concerns" which is the phrasing many of the commenters are responding to).