Standard prior in any field one is not an expert in ought to be "current expert consensus".
If the field is disentangled from reality, even the experts are no better than a random generator. Theology is one example. A lot of today solid disciplines could serve as another at some early point of their history.
The post hasn't argued for a non-consensual psychological theory - the situation where your advice would apply - but for the hypothesis that psychology is not a solid discipline. (Disclaimer: I neither think that psychology is bunk, nor liked the post.)
Theology is a conditional field, like complexity theory or mathematical logic (e.g. "assume P != NP, what follows?"). There are some smart theologists.
Scientologists claim mainstream psychiatry is divorced from reality. Mainstream psychiatry claim scientology is divorced from reality. If one isn't sure who to trust, just look at the output. In terms of theology, is the entire output of the theology discipline useless? Are you sure you are willing to throw away Aquinas, et al.? Psychology is even less controversial, there is undoubtedly many valuable things produced in psychology. On the other hand, what have the critics (or the alternative the critics promote) produced?
The road to the truth is paved with revelations; sometimes those revelations are uncomfortable. Also, you can never go back; it is impossible to unlearn something.
The problem is, if you go too far, those who fell behind will stop to hear your voice. You want them to be closer, and sometimes the only way to achieve it is to guide them to the truth. But the road is paved with the uncomfortable revelations. Oops.
So far, I remember two big uncomfortable revelations: the first is that we live beyond the reach of god, and the second is that the psychology isn't nearly effective as everybody thinks.
If I had been completely honest with the people around, I would have told them about House of the Cards. But I'm not. It is too cruel to say "Hey, your world-view is wrong and your competence is just an illusion" to the psychologists and soon-to-be-psychologists. Hence I'm afraid to say even innocent "Hey, I read a very interesting book yesterday" to the fellow CS students (because I don't know whether they have psychologist relatives).
This situation seems very wrong to me, but I understand that the reality is unfair and I'm lucky that I can be an atheist without fear of alienation, unlike the poor souls living in the bible belt. I'm just going to be very careful with my words concerning psychology. Of course I should be more cautious and patient while talking with strangers in *Guardian Of The Truth* mode, no surprise here.
But still.
Sometimes I wonder what I'm going to do if I really need to tell somebody that very often psychology is useless and sometimes it is even dangerous. What should I do to prevent their flinching from the truth? How to make the reality look more comfortable to them?