But what exactly are these people's interests? What are their expectations from the Clinton campaign? It doesn't always have to be something horrible, like allowing drilling on the eastern shore

It could be lots of things, it doesn't have to be anything specific. It could be future access, it could be that when new drilling restrictions come up she'll enact weaker restrictions than her primary opponent would have, it doesn't even have to be something bad. The specifics don't really matter at all, the problem has as much to do with the effect of the donation as the intent. It's hard to be against someone who supports you.

If I'm a rich oil tycoon and I donate a bunch of money to your campaign and I have been for years - without any stipulations or promises or intent to "buy" you - when it you end up having to make an oil related decision that that has a large effect on my bottom line it's probably going to be harder for you to make that decision. Maybe that's a good thing, maybe it's a bad thing, and maybe you'll make hard choice anyway, but it's unlikely that you can make that choice as easily as someone I never donated to could.

Besides that, you make the point that some of the people donating from those industries just want to see society progress and aren't thinking about their own interests and I absolutely think that's true and that many probably even know/think they're donating directly against their own interests but I think many of them are donating because they think the candidate they're donating to will be good for them(or at least will maintain status quo or be better than the candidate they're not donating to) and wouldn't donate if they thought otherwise - even if they like lots of other things about that candidate.