I understand why they did. Their frustration is understandable in in some regards, justifiable. Their problem is what they've chosen as their solution.
According to Real Clear Politics, she's winning in all battleground states except GA and NC, where he leads by 1 point. If he behaves as he has in the last two weeks, his numbers are going down, not up. Right now he's losing Republican support and not gaining anywhere.
If Trump was remotely similar to Reagan, you might have a point. They could not be more different. Furthermore, Trump virtually has no campaign infrastructure. I know, who cares? It's Trump. The rules don't apply to him, right? Well, that may be true to a point, but ultimately people have to show up and vote for you in order to win. For that to happen, you need a way to find the voters and get them to the polls. That's how Obama took almost all the swing states. David Axelrod built a superb GOTV operation in places like Ohio and Virginia - had extremely accurate and comprehensive data and a massive volunteer force. Trump has virtually nothing (far less than Romney had, which was obviously inadequate), and you can't just throw that together on the fly. It takes time and work. An active Twitter account isn't enough to win a presidential election. It you gets attention when you say stupid things on it, but it doesn't get people to the polls.