There's plenty of advertisers who have blogged about "My emails to Twitter stopped getting answered" around the time of the 75% layoffs. This is well documented.
What do you want the advertisers to do? To just keep giving money to Twitter even when all their contacts have disappeared? There's some pretty basic behaviors that have nothing to do with politics here that Twitter is failing at.
To say that ad sales has to be a manual, high touch channel is simply wrong. Perhaps you have staff on hand for large accounts, but why would e-commerce drop shipping headphone company #7 need to talk to a human?
Disney is most interested in making sure that Mickey Mouse / Winnie the Pooh / Zootopia is not accidentally shown next to furry porn. Southwest doesn't want its ads shown next to airplane disasters. Kellogs doesn't want "Itsssss GREAT" being shown next to the Ukrainian War.
As I said before: you can't predict the "X is being shown next to Y, please stop that" problem. Its impossible to predict X, its impossible to predict Y. You just gotta have email lines with these big companies and promptly issue your programmers / machine learning / data scientists the new algorithms to keep advertisers happy.
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Twitter is 100% the grounds where furry porn, Airplane Disasters, and Ukrainian War disasters are constantly being discussed and shared. Advertisers want protection of their brand, despite the online discourse.
When the tools aren't working as expected, the advertisers then emailed Twitter's API teams. All of those teams have been dismantled, the executives have been fired. With no one left to contact, the advertisers have begun to leave.