Just because one cannot explain a phenomenon using known physics doesn't mean they should outright dismiss it. A good many discoveries started with, "Hmmm, that's odd...".
And, science mistakes are good lessons, such as "why didn't we think to check that?"
I think you are not doing credit to the many physicists and science communicators who thoroughly explained why this was quackery. And in a world with quacks - people who have deceived themselves or are deliberately deceiving others - I think it is defensible for most of us to ignore people who claim to have violated the conservation of momentum with scant evidence.
If it had been thoroughly explained then there wouldn't have been anomalous experimental results. I agree that it's rather likely that we're seeing experimental artefacts rather than new unexplored areas of physical law, but we must scientifically explain the results or else be very cautious, in general, when declaring something to be impossible. As the joke goes, that is well known to be the surest way in science to eventually be proven wrong. Even if it turns out these pseudoscientific dismissals were reaching the correct conclusion; well, as they say, even a stopped clock is right twice a day.
I'm not claiming impossible. I'm claiming so unlikely that it's not worth our attention. The problem is that we live in a world of people trying to fool us. People trying to actively undermine the scientific process. There is a long history of charlatans claiming free energy; it's not feasible for us to entertain all of their claims.
Re: you are not doing credit to the many physicists and science communicators who thoroughly explained why this was quackery
To my knowledge, general intent to deceive was NEVER proven. Or are you using a different definition of "quackery"?
Yes, it appeared to violate known physical laws, but it was still possible that A) physicists missed a curious aspect of current models, or B) the existing models of physics are wrong or need tuning. It happens. Not common, but it happens.
But other people could reproduce the results, at least to some degree. If the scale had said 0.00000000 for the second tester, it would have died as a story.
And, science mistakes are good lessons, such as "why didn't we think to check that?"