[inglor_cz]

Beware of trying to explain everything with a single variable (in this case, inequality). For example, the 1968 unrest in France did not happen because of an economic shock. And some economic shocks did not produce meaningful mass movements.

Young people tend to be edgy in general and they lack the experience to recognize the slippery slope potential from edginess towards dystopia. Most of the time, the edginess stays on the Internet, though, and only a tiny percentage overflows to the streets. The human civilization is trending away from the "active rioter" towards the "keyboard warrior" mode of operation. Riots used to be much worse, even in the 1980s, than they are now. Possibly the Internet acts as a surrogate channel for all that hate?

What inequality does is, IMHO, help recruit older and more experienced people to a radical movement that would otherwise fizzle out without massive support. The Yellow Vests in France were a good example. Once the lower middle class lost the ability to support their lifestyle, they lashed out in a way more destructive way that random students could.

[Mikeb85]

During the 1960's the gini coefficient in France was nearly 50. Now it's in the 20's.

Considering the French protests were started by leftists literally complaining about inequality, and that inequality was much higher then than today, I think my explanation holds up.

[inglor_cz]

I think any explanation should also explain all the instances of countries where protests did not happen, even though inequality was high.

The best evidence for causality would be to demonstrate some kind of "dose and response effect", which isn't easy. The dreaded word "culture" tends to creep in, because some countries seem to have a lot more riot-y history than others. (France vs. UK vs. Spain).

[Mikeb85]

You're right, social mobility and overall standard of living matters as well. Also, how strong the state itself is and how decisively they can put down insurrection...