OK. Assume that is true. What's the harm in requiring ID to vote. It will make people have a bit more faith in the process, and costs next to nothing. Is it a poll tax? I think it's not. Would it stand up to a SCOTUS challenge? I think it would, it's a narrowly tailored response to a potential problem that is foundational to the US republic.
In that pool of non-ID toting people are, by estimates, something like 10 to 20 million aliens here illegally. Do you think Obama's presidential order implementing part of the DREAM act was meant as a craven political move with the sole intent to garner the hispanic vote? Do you think some of those 20 million illegals will be tempted, or coerced to vote in the upcoming elections, especially when there is no requirement to show any kind of ID to do so?
As far as examples of voter fraud, several people have offered them up. My own experience in Chicago as a kid is one such. I saw boxes of little manila envelopes each with a five dollar bill inside, and each destined to buy a vote for the Democrats. You dismiss those examples as "anecdotes".