There was a Washington Post/ABC News poll last week (the Post has an article about it here, including chars for some of the findings) which I thought was interesting and warranted a bit of discussion.
Obviously, I can't speak for anyone other than myself, but I thing the truth is a bit more nuanced than that. I am in the independent group of the chart, however I think that the majority of democrats both "stand for something" (their agenda) and "just stands against Trump"; I do not find the two options to be mutually exclusive at the current time.
The Democratic agenda, those policies that matter most, tend to include items which aim to improve the lives of the people (arguments can be had about the actual outcomes of the policies, but the intent is there). These include equal rights, the advancement of fair practices, regulations and oversight of unethical business practices, providing education and health care among other things.
In the current political environment, the Republicans, the party in power, seems to only have one agenda: to undo the policies of the last administration. They were vocal about this for much of Obama's presidency, and now that they've got control of the three branches they've got a clear path to do that (were it not for the in-fighting).
So, to advance the Democratic agenda currently requires the direct opposition of Trump and the Republicans. At this stage they way to do that is simply to try to preserve the advances that have been made, to minimize the damage that is done. Honestly, at this exact moment, there seems to be no hope for pursuing additional gains - there is a ruling party which is largely dogmatic about rolling back "the opposition's" policies (they've been promising for years that they'd repeal Obamacare, they have to keep that promise (if that's the only one they do keep), consequences be damned!).
One should view this as a change in priority based on the current climate. Ideally, politics shouldn't be viewed as a battle between opposing sides; the sides should have a mutual goal, and should only differ on the details of how to get there and be willing to work together along the journey. That being said, I'm going to use war as an analogy for the change in priority. The end goal of an advancing army is to reach a target (a goal); sometimes they can make progress and move towards that goal; other times they must protect the gains they've made, and resist falling-back. The agenda, the target, the goal is still the same; it is simply a change of immediate priority and tactics that are dictated by the environment - we are simply in protect-mode currently.
I do still believe that, overall, the democrats are largely about advancing the causes mentioned above. There are likely some who would be anti-republican in the absence of Trump. Sadly, I cannot say the same for the other side though. After eight years of opposition and grandstanding against Democratic policies, I have come to believe that the Republican party has moved firmly into the no-compromise, 'my way or the highway', mentality and they've demonstrated this time and again.
I have always been a registered independent. However, once upon a time, I might have considered myself more closely aligned with republicans. I still consider myself libertarian; now I include the additional label 'rational' to that. I am a rational libertarian: in an ideal world, the libertarian ideal could work - unencumbered trade, no regulation, free market economies, etc. ... let me live my life as I see fit, and I'll return the favor. But I know, rationally, that this is not an ideal world. Protections are needed, industries have proven themselves to be incapable of acting ethically without regulations, people deserve to be treated equally, and deserve to have equal opportunities in life. I find myself more closely aligned with Democratic policies than in the past. Given the actions of the Republicans of late, I find this a very good thing.