Um so lets be smart for a second and lets look at a picture of the East Wing

Then lets also look at the history of it.... hmm wasnt built until 1902 as an extension of the initial White House structure. The White House itself is still completely untouched. If we want to split hairs in 1942 the building was significantly changed... hell they only left of part of it to hide the bunker being build and then added a second story.

The quote you used is like using the Schumer quote that "everyday the government is shut down is good for us" did he say it? Yep. But he didnt say it on camera or the specific way he did.

I mean its not surprising they figured to start from scratch was going to be cheaper and more structurally sound. Thats just basic common sense.