My guess is that they are doing it to sway the uneducated (in terms of US political knowledge) to vote democrat. Imagine you are an immigrant, or a US citizen that's not too familiar with our government, and your thinking might go like so:

USA good -> USA democracy -> democracy therefore good

Now who do I vote for, republican or democrat? Well maybe I'll assume a democrat is for democracy and I have already decided democracy is good therefore I'll vote for the democrat.

I honestly think they’re referring to themselves and not US.