In defense of Hobbes...
Mark Granovetter came up with a threshold model of social violence (i.e., riots), which are usually composed of large groups of people - most of whom would never on their own chuck a rock through a window, burn down a store, or assault or murder someone, but all of these things can and have happened in riots. What he hypothesized is that violence in riots are started by someone with a violence threshold of 0, which then opens the door to someone who won't join in until someone else has, which opens the door to someone who requires 2 people doing wanton violence before he or she joins in and so on. In a sense, the violence acts like a social contagion and spreads until there's a break in the violence threshold.
https://www.commonlit.org/en/texts/t...ds-of-violence
This is a roundabout way of saying that it may not take a lot of provocation for a crowd of refugees to spiral out of control into a spasm into an orgy of violence sort of like a stampede at a concert.
On a slightly different note, but related to Hobbes, Peter Zeihan has waxed poetically about the potential impacts of a collapse in globalism and a disruption to the energy market. I'll summarize briefly (but, you should really go look him up on Youtube or buy his book "The End of the World is Just the Beginning"):
1. The global energy market is very easily disrupted; it is largely secured through the global order created and enforced by the US following WW2.
2. Agriculture is an *industrial* activity, not a pastoral activity. It requires significant inputs from the mining, chemical, energy, and industrial sectors to maintain yields (potash is mined, nitrogen fertilizer comes largely from natural gas feed stocks, which come from the energy industry, which also produces the fuel that is used to plant and harvest and distribute crops, and the planting and harvesting is largely mechanized as well).
Adding fertilizer inputs into soil has allowed humanity to take unproductive land or marginally productive land and make food grow on it. Take those inputs away, and that marginal land no longer produces crops. Ultimately, you get a 5-fold or more reduction in yields, with a resultant equal drop in population shortly to follow.
As an aside, a LOT of the world's fertilizer comes from Russia and Belarus. A lot of the developing world's surplus grain comes from Russia and Ukraine. China imports 80% of their energy supplies, and has (according to Zeihan) the 2nd worst statistics on the amount of inputs needed to produce a calorie of food (with Brazil having the worst).
In Twilight terms, GDW may have been optimistic about only half the population being dead 2 years after most of the world's oil production was destroyed.
As an aside and a sort of self-rebuttal to the argument that it all falls apart, the US is actually in a great position. We are (or could very easily be) completely energy independent, we grow an excess of food, are not dependent on long supply lines over areas we can't control to keep the lights on or the people warm and fed, we have more navigable waterways than the rest of the world combined (which is about 10x more efficient than rail in terms of energy and cost to ship goods, and rail is about 10x more efficient than semi-trucks, which are about 10x more efficient than airplanes), and our agriculture isn't heavily dependent on fertilizer inputs, and what we need we can get from Mexico and Canada