I get it, your perspective is totally fair. Part of the reason Democrats care only about donors (the Israel lobby is one of those donors) is because of the influence of money in politics, which is a direct result of Citizens United. If they don't care about their donors, they lose. The incentives are pretty straightforward.
There were great campaign finance laws on the books, but Republican-appointed judges have steadily eroded those over the years, culminating in Citizens United. We have to overrule that awful case if we are to ever have working campaign finance laws in this country again. There's only one way to overrule that case, and that's with Democrat-appointed judges. Those judges typically do not answer to donors and so don't have the same incentives you've identified.
There were great campaign finance laws on the books, but Republican-appointed judges have steadily eroded those over the years, culminating in Citizens United. We have to overrule that awful case if we are to ever have working campaign finance laws in this country again. There's only one way to overrule that case, and that's with Democrat-appointed judges. Those judges typically do not answer to donors and so don't have the same incentives you've identified.