I honestly am not sure where I stand on the debate over this. But I note that, even though people are divided over whether it's appropriate to publicize the names of campaign donors, almost everyone today agrees that votes should be confidential - even though there's a long history of political thinkers (e.g. - John Stuart Mill) who argued otherwise. I can see several possible rationales for publicizing financial contributions, but not votes. But all have holes in them.:
Contributions are more likely to make a difference to the outcome. Perhaps. But, at least in a presidential campaign, the likelihood of a $2800 contribution (the legal maximum for an individual donation in 2020 election cycle) changing the outcome is still infinitesimally small.Probably on the order of 1 chance in 1 million, or less.
Whether or not they influence the outcome, individual contributions are more likely than individual votes to influence a candidate's policy positions. Also, true, but also still highly unlikely to have more than a tiny chance of actually changing a policy stance of any significance.
Even though individual contributions matter very little, a large group of them matters more (e.g. - if a candidate gets lots of contributions from people in industry X, that might influence his positions even if one contribution does not). True, but the same thing is also true of votes.
Contributions are usually motivated by self-interest, while votes are not. The social science research doesn't support this. Most contributions appear to be ideologically motivated. Neither votes nor contributions align with narrow self-interest very well (at least not on most issues; there are a few exceptions,such as gun rights and smoking restrictions where gun owners and smokers are more likely to oppose regulation than other people, controlling for other variables). In most cases, a narrowly selfish person can do better by not donating money to politicians at all.
The ability to vote is more equally distributed than the ability to make contributions. True, but not clear why this supports mandatory disclosure. We don't require mandatory disclosure of volunteer work for a campaign (fewer people have time to volunteer than can make financial donations), donations of expertise, or use of various other assets that are even more unequally distributed than money is.
It's not financial contributions in general that should be disclosed, but only those to Trump, because he's so awful. If so, why not votes for Trump, as well? FWIW, I agree Trump is unusually awful, even as compared to other politicians. But that doesn't provide a basis for distinguishing Trump donors from Trump voters.