Because these are literal sky scrapers. Fire on a wood structure is a recipe for catastrophic failure. A fire in a large structure could have similar effects to those large high rise condos that collapsed in Florida from poor maintenance.

i think you're operating under 1) an extremely 1800s understanding of how fire-resistant a wood skyscraper would be and 2) a misguided understanding of where fire safety problems tend to come from in most contemporary buildings

wood is not uniquely flammable,[^1] and the vast majority of the problem in a fire is not going to be with the actual wood itself (as is true of steel, concrete, etc.) but moreso with the fact that we make nearly everything that isn't the building itself out of extremely combustible materials and we probably should not do that? as i recall that was the entire problem at Grenfell, where the cladding used was a flammable plastic that rendered any airgapping measures between flats useless and allowed the fire to spread uncontrollably. the fire at Grenfell also reportedly began from a refrigerator that was plastic-backed.

[^1]: it can rather trivially be treated to be fire-resistant--and as the person you're replying to notes has already been tested extensively and implemented in existing buildings to that end, and in multiple locales, just from a brief search on the subject