There is a corporation in Thailand called Italian-Thai Development corporation. It gets major infrastructure project contracts from the government with lower bids. A few of their projects, including this building, have collapsed in the past. They tend to save money by using cheaper materials, usually lower rated rebar and concrete. The inspectors were also a well-connected Thai architectural company who greenlit the progress.Do you have a source about the rebar story? It doesn’t sound credible.
The rebar manufacturer in this case is a joint Chinese-Thai company (you can't have solely foreign owned businesses in Thailand, only up to 49% ownership) whom they blamed within the first hours of the collapse of the building. It's easy to blame the foreigners.