I don't understand why capitalists are afraid of socialism...

[muriel_volestrangler]

12. Full-bore socialism is ownership of the vital industries by the people or workers, not by those with capital

Government policies that benefit corporations or rich individuals aren't socialism - socialism is not just "anything that's not total free-market economics". There are other economic systems than capitalism and socialism - mercantilism, for instance (which can often involve subsidies or state-granted monopolies to private companies - think of the East India Company and tea imports to the Thirteen Colonies).

There are some things in the USA that are socialist - a water company owned by an elected authority, for example (in England, these got sold off to capitalists, and what a disaster it's been). Widespread socialism would mean the conversion of companies into worker-owned, or state-owned, enterprises, by law - with or without compensation, depending on the politics of the government. The chances of this happening in the USA are miniscule, but capitalists find it worth stirring up fear of it anyway.

Mamdani's idea of city-owned stores is a form of socialism, but it's not like he'd force an owner to sell their store to the city; this would just be another competitor, which may turn out to be able to offer better service and/or cheaper prices.