He said he has no opinion because he's not a physicist or a structural engineer, so he's not going to try and debate the minutia of what happened in WTC 7. If you watch the whole video, he makes a well-reasoned case as to why he thinks the conspiracy claims are bogus, saying that if there were any merit to the conspiracy claims, they would be published and peer-reviewed by the physics and engineering community, and how easy it would be for these conspiracy theorists to bring their claims and data to the scientific community for analysis instead of the tinfoil hat n' pajamas youtube scholar community.
It's funny how Chomsky always says "I have no opinion on that" whenever somebody comes at him with bullshyt lol. I guess that's his way of being polite. I remember I was watching him on C-SPAN taking calls once and it was like every goofy ass HL
called in with their pet conspiracy/new age/pseudoscience topic question. I guess he attracts those types because his views are so outside of the mainstream. Caller after caller kept rambling about 9/11and banking conspiracies and even more off the wall shyt...one lady asked him some question about "goddess power," whatever that is and Gaia. He just kept repeating "I have no opinion on that" over and over on those types of callers.