I'm not an expert on this, but my understanding is that concerns in this area often center around donations to political action committees, rather than to campaigns directly, although both are matters of concern. A "SuperPAC" backing a candidate may receive an unlimited amount of donations, and may spend it to support their candidate as long as they don't coordinate too closely with the candidate's campaign. They must remain sufficiently independent for it to count as independent expenditure, in which case the donations and expenditure are unlimited.
Unlike regular political actions committees, which can donate to candidates and must report who they receive donations from in turn, Super PACs are not required to report their sources of income.
This essentially means that people are free to spend unlimited amounts of their own money talking about their favored political candidate, though they can't donate unlimited amounts to the politician's campaign.
I don't have a strong personal stance on this issue, but I consider the ruling fundamentally fair. If I want to spend an unlimited amount of my own money buying advertising space to raise awareness around global warming, I can do that. That's speech, and large-scale speech takes money. I should be able to do the same thing to support a political candidate.