Good question - but it would take a while to explain. I've explained this previously, in several responses to others. Perhaps it will help to offer points:

1) I don't think people should vote emotionally for the person who seems to represent them. Emotivist politics developed especially in the early '80s (and earlier), and appealed to church groups, angry Americans, nationalists, and others who often voted because of how they felt. Ethicists call this 'emotivism' (A. Macintyre, C. Taylor &c). Some of these voters are so-called one-issue voters, who will vote for the candidate who promises to make all abortions illegal. Or the vote for the person they think they can have a beer with. I think we should never vote like this, because Fox News and other propaganda outlets have been pushing this agenda which favors Republicans and authoritarians, with the assumptions that - the entire government is shit - so elect the few people who will reduce government and you can trust them to look after you. But who takes over when government agencies can't function? Corporations. Will the authoritarians like Trump keep those corporations from poisoning your water. No. We don't have to like or love the candidate we vote for. We have to respect that they'll do something for the 99%, or they'll be voted out office. In fact term limits for congresspeople are long overdue.

2) Both political parties and all politicians are not the same. Fox and Breitbart want you to think they're all the same so that you won't believe in democracy, and so that you won't vote. If you don't vote, the authoritarians and Republicans win elections with low turnout. Republican gerrymandering and special voter ID laws that keep people from voting help them get into office. Are there corrupt Democrats? Sure. What's the solution for you? What can you do to change Government? It's possible to vote corrupt politicians out of office, while supporting others to replace these corrupt, carreer politicans. More people should vote in order to make this possible. Senators for my state are Republicans, but much of the state has the lowest number of educated people, and low incomes. Larger cities vote blue, but it doesn't matter for the Senate seats. The rural vote goes to Republicans, although Republicans are helping corporations take over US governance in several sectors that push these poor rural voters deeper into poverty. Wages have not kept up with inflation for the past 40 years because of the majority of Repulican decisions that de-regulate corporations which are abusing workers.

3) Why support Democrats?: not because we should love them, and not because there are some corrupt, career Democrats, but because they are the ones writing bills that will help the 99%. Republicans are blocking those bills. The election reform bill was blocked. The jobs bill is currently being lobbied against. There are many other examples of Democrats trying to pass laws that help the 99%, dating back to FDR's New Deal. A rich country like the US should not have so much poverty, or extreme income inequality, or problems with healthcare (addressed by Obama, though it wasn't perfect), problems with clean water, problems with the environment. Just look at the politicians who want to work on these problems. Are they Republicans? No. Republicans are the ones who love deregulation and blocking any legislation that could help you. (The also tried to block and repeal Obamacare dozens of times).

4) Politicians are public servants. Worker ants like us have a vote, and a way of supporting politicians who want to be public servants. If those public servants are in office more than 2 or 3 terms, something's probably wrong. A good public servant might be someone we cannot have a beer with, or someone we can relate to, but none of that matters. What matters is respect. Is the legislator helping the 99%? If so, he or she might be old, or black, or hispanic, or have learning difficulties, or be kinky, or whatever, but they deserve respect if they are genuinely helping the 99%.

I'm not sure this answers your question, but I hope it explains part of the answer.