[gjhan]

In the context of this paper, the DSs are significantly smaller than galaxies, but JWST doesn't have enough resolution to distinguish a galaxy from the much smaller DS.

In their DS model, what seems to limit the rate at which the DM annihilates is that any interaction between DS particles has a low probability of happening (a cross section). We can imagine this as particles just whizzing around each other, gravitationally bound (i.e. confined to a nearby volume) but so small that they have a low probability of actually interacting.