It isn’t relevant whether their beliefs were correct, only whether there was credible evidence to support them. If the subjects held their beliefs despite lacking evidence for them, the argument stands even if those beliefs were true.

This suggests it’s unrealistic to expect the opposite outcome, but does not challenge the conclusion drawn. It’s another possible conclusion of the argument, more strongly supported than the actual conclusion.

It isn’t relevant that the information was inaccurate or misleading, only that participants first believed it and subsequently learned it was false. This doesn’t say the subjects were aware the statements were false or misleading.

This suggests subjects held their beliefs based on other credible information. Though their original basis was debunked, they had other evidence supporting their new beliefs.

This doesn’t change the fact that subjects developed new beliefs based on that information, then refused to change them upon learning that information was false. It makes their behavior more surprising, but does not challenge the argument.