> Just as it someone doesn’t know how to fulfill any other obligation, he should learn how to
There is a profound differences between learning how to do schehita or how to give tochacha. Mitzvot bein adam l’Havero require understanding the other person. Same tochacha may inspire one person and leave another one depressed. For some smart kid, when the Rav explains that he runs the shul according to the people who are there, it may be a step into Rabanut, sociology or psychology; for an emesdik Avira it was a reason to reject the Rav.
So, I am all for people trying to learn it, but do not expect everyone to succeed! Even if they learn everything from their teachers, it might not help – as generations change, and what worked 20 years ago might not work now.
There is one safe method of tochacha that has less side effects – demonstrate the correct way by your own behavior.