Who knows. Probably when they are pushed some more. Most populations you'll find will tolerate more abuse than you think; isn't it easy to measure the abuse factor of a peoples' by just measuring and varying the things like food, cost of living, basic comforts and then striving to meet just above the minimum threshold?

And, finally, when you as a leader cannot meet those needs any longer, you push for war as the chimpanzee alphas do and prolong your position of power even longer.

edit: to answer your question, I think when they are less sick, have more perceived power and agency. The Americans of today are more sick, more self-perceived as disempowered, and in general a naive and gullible, cowardice people.