Nor do your feelings that poor people are de facto dumber than rich people.
They're citizens of our society and therefore any and all societal decisions will directly impact them. It is our right to have some amount of influence over decisions that directly impact us. You, yourself, understand that.
Why then should that concept not extend to the poor? This question is purely rhetorical - I know you don't have an answer, and probably the least embarrassing way forward would be to just say nothing. But, that's the perspective I'm addressing here and why I didn't bother to explain why the poor deserve those rights. I don't need to - I get those rights, and I like them, so that's the status-quo.
Nor do your feelings that poor people have less informed, less useful, less credible, less valid, or less valuable opinions than rich people.
Better?