Now many HKger said blaming on bamboo scaffolding is a conspiracy from China to replace it with metal, they want to preserve it.

It's not because of the bamboo, it's because of the green mesh. Someone somewhere skimped out on the fire-resistant version and instead used something that looked the same but extremely flammable, that was how the fire spread upwards so quickly. There are videos demonstrating the difference in the green mesh types.