Most political organizations can be similarly characterized as dictatorships with oligarchies; depending on what level you look, pretty much all of them can.
Consider your last question, though: What do you mean by influence?
Multi-nationals based in the US and elsewhere already had plenty of influence in various forms before this decision. Now...they can pay for commercials. They can now make blatant, public statements of support in front of American customers, roughly 40% of whom will take some degree of umbrage or offense to this no matter who they support.
Yes, there are many forms of influence already, lobbyists and the such. My intent was to say - there is now one more way that large multi-national entities can directly shape opinion by marketing spend. This makes the contribution of the individual without money less and the consolidation of power (influence) in the hands of those with money greater. By the people for the people moves towards "by the corporation, for the corporation".
Consider your last question, though: What do you mean by influence?
Multi-nationals based in the US and elsewhere already had plenty of influence in various forms before this decision. Now...they can pay for commercials. They can now make blatant, public statements of support in front of American customers, roughly 40% of whom will take some degree of umbrage or offense to this no matter who they support.
How does this hurt democracy?