Usual suspects

Out of curiosity, why is each story about electronic voting machines jumping votes always about machines incorrectly recording votes for the republican candidate? Did I miss something?

P.S. Yes I missed these stories:
- Can You Count on Voting Machines? where "some Santorum voters complained that the iVotronics “flipped” their votes before their eyes". [Thanks Pierre for the link]
- Votes Reportedly Flipping from Repub to Dem in TN. [Found from Mark Crispin Miller's site]