The goal may be as simple as scoring a few free donuts, or as sinister as preventing the store from doing business. in other words an attack by anachists interfering with capitalist enterprises. Destroying a $2000 machine suggests the latter, but it could also be mindless vandalism. How can a fast food restaurant stay in business if they are afraid to let more than 2-3 people in the store at once?
If 10 white haired grandmothers from Maine showed up, there would be no problem with their numbers.