Political donation spam is a plague. I ran a donation website in 2018 and 2020 that split up money among many candidates, and by far the biggest complaint was the flood of email that came after using my site. In 2018 there wasn't even an opt-out button on ActBlue. In 2020 they added one, but the default was still to share your info. But it doesn't even really matter, because campaigns continue to buy and sell donor lists, so once you're in the system, you'll never get out.
It's a legal problem, in that spam laws simply don't apply to political campaigns.
But fundamentally it's a collective action problem. Excessive fundraising messages hurt the overall brand of the party and politicians in general, but for each individual politician, the advice from consultants is that each extra message has marginal value. This is actually true for out-of-district messages—they might get your money, but if they piss you off, they still don't lose your vote.
There is some movement to try to fix this.
Oath (oath.vote) is an ActBlue alternative that doesn't share your phone number or email address with campaigns. They can't erase you from the system, but at least they're trying to do the right thing.
Eventually, if groups like Oath, Crooked, Emily's List, etc. can all team up and say, hey, you won't get donations through us if you keep spamming people, we might see some change.
I assume things are also bad on the Republican side. It would be easy to say it's good if their brand suffers—but actually, I want them to start behaving more responsibly, including in this area.