"Tracy Schmaler, a Department of Justice spokeswoman, said it was because 'a malicious code was found contained in a Web ad on Drudge.'

Schmaler also said the request to stay off Drudge wasn’t politically motivated and said it was sent only to the office in Massachusetts. She also said other popular sites were later found to have potential viruses, including ESPN.com."

I'm not seeing the political motivation here. I have Chrome set up to auto-black anything with shady code, and have had it trigger on a whole variety of websites, including political sites of both left and right (edit: based on the ads, not the content). There's a lot of malware out there.