I generally prefer small business, but the ‘big = becomes evil’ phenomenon just might be because of identity centralization. If your city has a hundred bakeries and one of the bakers turns out to be evil, it mostly just reflects back on him. Replace those hundred bakeries with a single large one, though, and suddenly one evil person reflects badly upon the entire organization.

Edit: just a reminder to support local bakeries, because they are usually tastier than big ones. Bad example.