Talk of melted steel is not evidence; same as talk of Bigfoot is not reality.
Physics is required. If not physics, critical thinking;
Hey, don't tell me. Tell Astaneh-asl, Ghoniem, Leslie Robertson, Richard Garlock, Keith Eaton, Pete Tully, Ronald Burger, James Williams, William Langewiesche, Larry Keating, Richard Riggs, Mike Donoho, Don Carson, Alison Geyh, Edward Malloy, Greg Fuchek, Herb Trimpe, Philip Ruvolo, Ken Holden, Guy Lounsbury, Glen Klein, Maddalena Romano, James Glanz, fire chiefs, firefighters, ironworkers, other pile workers, first responders, New York Sanitation Workers, the ASSE, the NEHA, RJ Lee, the 9/11 Commission, and the USGS.
Tell them that their evidence is lacking and their testimonies are not credible, according to you. Tell them that you, armchair internet "debunker", need to see their data, because their testimonies don't match what you believe about 9/11. Tell them that
you are more likely to be right than they are, simply by virtue of the fact that you sit at home typing on your computer keyboard, while they do dumb things like help out in a tragedy, analyze evidence, do aerial surveys, take measurements, write reports and communicate to their peers or to the general public.