Why do Voter ID laws offend minorities?

As I gather from this article, asking for identification when voting somehow suppresses the minority vote. I don’t understand why.

Doesn’t it make sense to protect the integrity of voting by asking someone to prove identity? It isn’t hard to get an ID card if you don’t want a driver’s license. I assume they have one to buy cigs or alcohol (assuming one drinks or smokes). Also, why is it a race issue?

Someone enlighten me, please and thank you.