All the examples on the splash page are current Democrat priorities. Even if you are left, you are unlikely to agree with 100% of one party's platform. (If you do, start thinking critically please.) Can this tool be used to support your own priorities or is it just a retweet/amplify button for the Democrat party line?
While there are some topics where I agree with both major parties, and many issues where both are near equally bad, I have yet to come across a national policy issue where Republicans are better than Democrats (even if the Democrats' policy is still not great). So yeah, I don't agree with one party 100% of the time, but I will support them 100% of the time over the alternative.