Creative Speculation

" He ignores potential damage to the fireproofing..."
No. You assume fireproofing may have been dislodged even though there's absolutely no evidence of that.

" ...he ignores the added weight that each assembly had to support."
Nope! In the towers 1 and 2, a large part of the mass is visible going over the sides and into the air as dust and the redundancy of the structure was adequate to support what was already above before the impacts. There was less weight! Not to mention building 7 which went down and had no additional weight added yet it fell at near freefall. Your sophistry will not flush!