Bruce, it's not so much that the Republicans are to blame for all the overzealous and illegal voter roll purges as that they are going out of their way to divert attention from the very serious problem of legitimate voter disenfranchisement by distorting and sounding exaggerated alarm bells over some small-scale attempts at voter registration fraud. Even though voter registration fraud is far, far less likely to have much, if any, impact on the election results.

Still, the Republican party HAS been pursuing voter roll purges much more aggressively in many heavily Democratic leaning areas than in most Republican areas.   And even if they were overzealously pushing for voter roll purges across the board, as the article points out, new registrations this year have been very disproportionately Democratic-leaning voters. So if the attempt is just to purge the rolls of voters registered in the last year -- or in any way to suppress the vote across the board -- it will have a disproportionately negative effect on Democratic votes.

But the bigger issue is this:   Is it reasonable or fair to disenfranchise dozens or hundreds of legitimate voters for every non-eligible voter you prevent from voting?
It seems Federal law says it's not.

Purging voter rolls within 90 days of a Federal election is illegal unless the person has died, moved out of state, or can be demonstrated to be ineligible for some other reason. (The burden of proof is on the state.   
You can't purge T. Boone Pickens from the voter rolls in Texas 2 months before a Federal election because you notice that Social Security has him listed as Thomas B. Pickens.

Further from the time of a national election, you can challenge his registration and give him a chance to show that his driver's license and Soc. Security card are for the same person.   But not this close to an election.   Government inefficiency or bureaucratic ignorance are not an excuse.

Anyway, these problems are very likely to suppress the Democratic vote much more than the Republican vote, regardless of where and why the problems originated.