When talking about why things were done the way they were done that day and in the days following, I think we need to remember what had happened.
On the morning of 9/11/01, FOUR commercial jets were hijacked. FOUR. That alone had never happened before. From a security standpoint, that alone is a big priority, figuring out how that many planes were hijacked at basically the same time.
Two of those planes were intentionally flown into two of the biggest buildings in the US, buildings over 100 stories tall. Again, has never happened before. Rescue plans didn't cover that sort of thing. They were simply unable to rescue many people, before the towers came down, there were people that rescue workers already knew could not be saved.
One of those planes was intentionally flown into the pentagon. One of the most important buildings to the defense department.
Al-Queda claimed responsibility for it. Believe them or not, they claimed it.
Every single plane in the US was grounded. Every single one. Every single airport was refitted with new security measures. Have you ever been at the airport when one or two flights gets cancelled? Imagine that chaos times every single plane in the US. Every flight headed to the US was prevented from landing in the US, so flights were rerouted to Canada, Mexico, some turned around and headed back where they came from. People were stranded all over the worldSome planes were low on fuel. I have heard that some pilots, low on fuel, also claimed they had been hijacked, just to be able to get on the ground fast, due to their fuel situation. I can't substantiate that, that's just something I had heard.
Rumors were flying everywhere, despite or maybe because of this day and age of immediate news and live video and such. Some people thought the Sears Tower had been hit. People thought more planes had been hijacked. People thought the White House had been hit.
Power was out in many places in NY. Thousands of people were missing. Phone lines were overloaded and communications were difficult. Many businesses in the area were damaged and or destroyed.
And then, in November, another plane crashed in NYC. The first thought is of course that it was terrorism, and Al-Queda claimed it too, but it was later discovered to be pilot error. But I don't think it can be dismissed when talking about the whys and hows of the investigation, since clean up and investigation were still going on when it happened.
Now, with all that going on, with the massive recovery that has to take place from all that...I think it makes perfect sense for the collapse of a building known to be damaged as a result of the two larger buildings coming down, to be relegated to low priority. There was so much else that was just more important. There was SO SO SO much going on that day and in the months afterwards. If mistakes weren't made and if parts weren't skipped over...THAT would be the weird thing.