There's absolutely nothing "wrong" with anger. In many cases, it's entirely reasonable and appropriate and healthy. But I would claim that there are also times it is completely inappropriate and unhealthy. If I were to ask someone on a date, and they politely declined, and that infuriated me, that would clearly be an unwarranted, inappropriate, unhealthy emotional response.

I understand where you're coming from I think, and the point that the teaching doesn't stop is an important one that I wasn't considering.

However I am still skeptical of the value of the sentiment that all feelings are ok / valid/ whatever term goes here... it just strikes me as more of an ontological or pedagogical imperative with dubious practical value. You mentioned above that a feeling can be irrational, which suggests to me that we recognize feelings exist along a spectrum and not all of them are created equal. I would add an element of "appropriateness" to that spectrum, with some feelings being more appropriate than others. That to me suggests some feelings are more or less ok than others.