The manufacturer for even bothering to make cladding that's flammable

People are running their mouths assigning blame without knowing the first thing about the technology involved.

The vast majority of construction-grade commercial thermal insulation is flammable. Off the top of my head, the only big one that outright isn't flammable is fiberglass, which however is not suitable for exterior applications where it's exposed to the elements 24/7 for decades.

However there are different ways in which a material is flammable. The type of insulation used in this tower is legal in most countries (from the materials sheet, basically every developed country), however in some it's not legal for buildings above a certain height because it's judged to be too dangerous (likely because of the effects of wind and updraft, although I'm a materials guy not a fire guy). The more expensive version is the same material with a fire-retardant additive, which means it will still catch fire but burn more slowly, produce less heat and have shorter flames, all of which contributes to a possible fire spreading slower.

Finally, we don't even know yet if the material was applied properly. The insulation is sandwiched between protecting aluminum plates, which means the weak spot for it catching fire is at the joints. Shoddy or rushed installation can leave the joints exposed, making it immensely easier for fire to spread since it doesn't have to deal with the aluminum.