A corporation is like a computer program. It has a purpose (making loads of money), and a methodology to follow to do so. If a computer program wiped your harddrive, fried your CPU, and burnt your house down, you wouldn't swear a vendetta against the software, you'd hold the person who wrote it to account. Likewise, corporations are automatons. If a corporation does evil, it's because its leadership is evil.

As automatons, corporations cannot have morals, because they simply follow their programming. You, a flesh and blood human, should feel no obligation to a corporation for any actions they take, for the same reason you don't write letters to a bollard thanking it for stopping a car that might have hit you.