If the Tochacha (however you pronounce that) is given gently and with genuine concern to help the other person get it right, it is almost always accepted gratefully, and everyone wins.
It is most certainly incumbent upon you to do so in most cases.
If it is done in the form of rebuke, you are likely to get less favorable results.
It is most certainly incumbent upon you not to do so in all cases.
I often hear people pronounce Hashem’s Name as, “Ah-doh-noh”, forgetting that even if you pronounce a cholam as “oh”, the Yud at the end of the Name is still there. I wonder what Rav Miller v’siyato would say about this.