Yep, I know exactly what it means, I can also recognize bullshit when I see it, and you're full of it.
If you knew what it meant, you would not have made the comment you did.
Say you have a bowl of red & green marbles where it is 20% red.
If I take some out & put them in a different bowl & this bowl had 40% red marbles, then it would be disproportionately Red even though there were more green marbles in both bowls.
Suppose that there are 40% of the people at are Republican & 40% Democrat & 20% other. If we stopped a million people at random from voting, then the resulting loss in votes would coincide with the expected.
If you stop a million poor people from voting, you stop a sample that is disproportionately poor & thereby disproportionately Democrat voters.