>> Ad hominem? Really? Is the study good or not? <<
It’s not ad hominem to question someone’s credentials when they’ve made an appeal to authority.
>> Is the study good or not? <<
I don’t know. That’s the point. I can find all sorts of people claiming God knows what on the internet. The purpose of citing the fact that it’s been published in a medical journal is an appeal to authority. It’s a way of saying, “a lot of people who are experts at designing and interpreting the results of a scientific study confirm that this was a well-designed experiment.” The fact that it’s a fake journal destroys the appeal to authority.
Did you read the study? For anyone objective, that would happen before commenting on the veracity.