Professors will often extrapolate their findings for possible meanings but in the actual study the conclusions are more scientific. Professors needs grants, they say those kinds of things at conferences and to reporters. Another reason why science journalism is bad.

Evidence that an ENTIRE field of study is worthwhile will not be presented to you in this kind of format. You need to either do your own extensive research if you want to have an educated opinion.

I'm also not sure if you really understand how science, like biology or neuroscience, works in general. I work in a behavioral neuroscience lab with a much heavier focus on neuroscience. We study nicotine's effect on fear conditioning. So we test different areas of the mouse brain for neuron activity as well as perform various behavioral tasks after they're injected with nicotine. So we recently got a result that said mice who were injected with nicotine and also had fathers who were injected with nicotine were exhibiting decreased learning. It's not like the computer prints out a reason as to why this is happening. As scientists, we make inferences on why this is happening and there may never be evidence as to why. We'll have educated guesses but may never be able to get that concrete proof. But we publish the results, talk about what we think was happening in the discussion section of the paper, and other scientists will cite our educated guesses in the future. All scientific research has flaws and can't provide the kind of evidence you want. All research needs to be looked at with a critical eye. You're ascribing this to psychology alone because you think it's a field that's easier to understand.