The main reason “the experimenters” can not address a lot of criticism is that the only team that ever ran an apparently successful test that was controlled and documented to a standard that made it through peer review - that small group at Nasa, aka Eagleworks - does not even exist anymore. And afaik there is zero funding at Nasa to continue related experiments. They did pay a good part of the experiment out of their own private pockets, and i do not even know if their test article still exists.
All the experiments that are public are super low budget. Cause the results do not justify higher budget research. The ones that have the highest claims of success are by the original “inventor” and have no publicly confirmed experimental base whatsoever - and every day without a public and controlled demonstration undermines those claims.
So we are largely left with enthusiast/amateur experiments, who do take a lot of effort and care, but can obviously not provide the same high quality data as a fully funded laboratory could.
Afaik, the only public experiment that might continue on a level that can make it through peer review and build on Eagleworks previous work is some navy research lab looking at the EMdrive. But i have no idea if that is just another small 2 man low cost experiment within a larger navy research lab, or something more serious with a real budget.
Imho, unless the original “inventor” puts up a convincing public demonstration at some point in the future, nobody will invest large amounts of money into investigating this kind of drive. Rightly so, investment should scale with evidence.