I agree suppression of an emotion is never good! Furthermore, I'd be really careful making assumptions about how any part of Buddhism is taught in other cultures.
As from my own experience, in my family I was taught to suppress "negative" emotions, and Buddhism has been the most awesome thing ever in helping me come face to face and be with my emotions, and learn to express them productively.
That said I took a similar tact naturally with my own children by teaching them it's ok to be angry, it's ok to be furious, but take a close look to see what's going on there. I didn't quite have good enough understanding then as I do now, but my parenting hasn't finished even though they are grown:-)
My point is kids can be taught to be with and express their emotions in healthy ways, in what we would call Buddhist ways without suppressing.
Anger never disappears completely. Even Buddha got angry. But it's a fleeting thing. It arises, you see it, then you shift gears into a more productive way of dealing with the situation. That in and of itself dissolves anger.
I think it's either a misunderstanding or a myth that Buddha was without emotion. I've read suttas where his annoyance was apparent, but he calmly goes into make a point without giving into unproductive behaviors such as yelling, swearing, hitting, etc. Though he does call at least one man a fool. lol.
Where I used to avoid my anger and stuff it, now I find it fascinating to work with. Anger arises in a big way, I recognize it, and then I immediately go into, oh what creative ways can I come up with to resolve this problem without giving into yelling, without telling someone they're a blithering idiot. In doing that, trying to find creative ways of expressing my anger, I find the anger soon just dissolves on it's own. But suppressing anger causes it to fester, causes thought stories to build and build until one explodes.
I do find generally irritation harder to work with than anger, as it's more subtle, justifications for it seem more powerful.
Calm people are not without anger and they aren't suppressing it. They've learned to redirect that energy into a new ways of solving problems.