The crew Fcuked up. (I can't believe they took 50 seconds to initiate the go around following ATC's directive. I am sure there are many other destinations that Thai goes to in the 777 that require other than ILS approaches.
I think the evidence that they took 50 seconds to react is very tenuous and I think the ATSB has been mischievous in the claiming this. Firstly, from the time log in the ATSB report its 47 seconds - not the 50 they use for the sensational sub heading, secondly it relies on the interpretation of the initial Thai response which the ATSB records differently in the body copy and Appendix B together with another call which the ATSB record as unintelligible. The ATSB have been found to change radio transcripts previously. It may be that case here. It was (from memory) 34 seconds until the second ATC radio call. If you start the clock there, then the Thai crew reacted promptly.
The ATSB report s not good enough to make these accusations. But it reads well and its only when you spend time to piece together fragments from different parts of the report to make a complete time line that it becomes evident.
Groundspeeds derived from the reported calls don't make sense either. I suspect the position or time of some calls may not be correct, which would change the flavour of the incident too.
The Thai crew did something bad. But the ATSB report is not sufficiently good to determine exactly what it was - in my opinion.