I have seen many a democratic initiative ruined by trolls, bot accounts, duplicate accounts, and assholes. The best way to ensure that democracy doesn’t spiral into Haiti is to allow only financial contributors of $5 or more to vote (once the boss man has his contributions system up and running). You want to help build this community? OK, then put your money where your mouth is. To be clear, it should still be one vote per person, whether you donate $5 or $500.
That would mean that many of the people which make up the community, but physically do not have the money to donate to these services (no matter how much you wanted to) would be completely left out of the equation on an important part of the community.
It would eventually lead to all the content on this instance or the threadiverse as a whole to be dominated by people richer than you which are able to afford this, which can then shift the content which they would like to see to the top of magazines.
Additionally, a sub-culture would likely form which would shame users for not being able to vote due to afford donating.
TL;DR:
Making votes donor-only poses a threat to the neutrality that comes by default on these platforms and incentivises hostile subcultures which would make the experience worse for a big part of this instance and potentially the threadiverse as a whole.