I think this may be "Facts to Fit the Theory" by Christopher Anvil. I found it in the collection "Interstellar Patrol II - The Federation of Humanity" It can be found here.
This is a short story, published in 1966, in ANALOG. There is a planet under threat by evil alien invaders, and the inhabitants of the planet were both pacifists (practicing 'self-control') and opposed to the methods of the Federation, who was otherwise offering to bring them under protection. There is a series of hijinks, wherein the federation tries to get a treaty signed (to save them from the invaders) but which are mysteriously foiled by the inhabitants, due to religious objections.
The invasion happens, or at least the evil aliens land, but each aggressive act they attempt is foiled by seemingly-natural causes (while the inhabitants fail to otherwise fight back), until finally the younger colonists lose their tempers and summon storms & the like to interrupt a large ceremony with a planned atrocity (meant to subdue any resistance). The local adults do scold them for lack of self control and the other damage caused by the large storms. The story ends with the federation observers trying to figure out how to report this turn of events.