I wouldn't say "nobody." I am personally aware of people who have, for example, turned down money from Yuri Milner/DST for reasons that were at least somewhat moral in nature. So it does happen. But these people had other good options so it was really a choice of who they were going to take money from.
It's when you don't have a choice or a questionably moral party offers significantly better terms that it's hard to turn it down.
Just curious, what's the moral problem with Yuri Milner? I don't know much about him except that he's Russian, which I sure hope isn't considered a moral problem in its own right.
It's when you don't have a choice or a questionably moral party offers significantly better terms that it's hard to turn it down.