I’ve been told that what Trump did is different because he was paying off both at the same time instead of supporting one and then switching to the other. Also, because Trump gave double the amount to Republicans (including Charlie Crist, not sure if that counts) as he did to Democrats. And also because this gave has given millions and Trump only gave half a million over so many years.
The one kind of donor often demands major payback, the other is trying to get access and a little help from being totally taken out by whoever they donate to.
Does that help?