Because people have the right, under law, to create corporations and benefit from them, they inherit much the same right to act in the interest of those people as those people have. [Yes, this has probably been over-extended in the Supreme Court case that lets them do political donations to their hearts' content]. However the core idea in the organisation of a society is that laws lock in rights and expectations; if I set up an organisation with certain rights, then I have to right to expect to see those right protected.
Specifically if I invest money in a corporation with certain rights, I have the right to expect to see those rights not tampered with. What you are proposed is to overthrow that principle - technically this constitutes a breach of the constraint on the Congress not to pass a 'post facto' law - see section 9 of the US constitution, Whilst you may regret this situation, to assert that the situation can be reversed is not legitimate.