Corporations inherit their rights and privileges from the people in them. Because a corp is in fact just a series of individuals in a trenchcoat. (This would make immediate sense if we had not let grammar decay and you implicitly knew corp = plural)
Those people did not lose their individual rights; they are still free to donate using their money. Corporations are not people even if they are made up of people.
The people making up the corporation can all vote as individuals and the corporation itself has no vote. This is no different.
people are corporations. I hardly exist as an individual in america. I do not own anything, my company does (my company employs only me and soon my daughter when she is of age), I do not buy anything, my company does. I don’t have phone service or internet service or practically anything under my name. and my company (me) has about the same rights as you, an individual, except of course a lot more cause capitalism be capilizing :)