>just as dangerous as governments

Corporations don't have nukes or concentration camps.

The Black Hole of Calcutta is a widely known example of what can only be considered a corporate concentration camp of the (at the time privately owned) British East India Company...

That is a bad example indeed. The event of the Black Hole of Calcutta, where soldiers were rounded into a tiny dungeon which few survived, was perpetrated against British soldiers working for the East India Company by the governor of Bengal, Siraj ud-Daulah.

They could easily get them if we didn't prevent them from doing so.

Corporations have nuclear power plants that can be just as dangerous. Corporations can feed the masses miss-information, that may lead to destabilisation of a society by making them vote for the wrong person.

Corporations build unsave factories that kill 1000s when collapsing (see Bangladesh). Corporations will add addictive substances to food and sigaretes you increase sales, in the process killing millions.

I agree. The danger isn't simply "Big Government" or "Big <Whatever> Corp.". It's the concentration of power, whether by private or public entities. Private entities will abuse/buy/influence any power structure that happens to exist, to server their interests.

At least with a corporation you understand their goal completely.

Not really, unless you can listen to every meeting or conversation and read every document.