They as a candidate don’t, the campaign as a whole is important to support though. Particularly if it can be shown that the funds come from small doners it shows popular support. I would rather see a crowd funded candidate with millions of $5 donations than a handful of super-pacs funneling dark money into it. It’s exactly the kind of problem that citizens United caused that we need to revert to show the popular will of the people.
The whole concept of corporations as distinct eternal entities could use a reworking. From copyright, to liability, to corporate ‘speech’, it all shields to interests of the well heeled from responsibility for their actions. Some level of separation from an individual is needed or no small business would ever date take the risk of starting up, but at a certain point somebody needs to own the actions of it. How we define that is beyond me, but for now I’d take removing non-breathing entities from the voting pool and political funding as a start.