Loonies
I've seen Democrats in hot water labeled as Republicans, too. It happens. I didn't assume it was an evil conspiracy back then.
The technique most often used in the press is to simply not mention the party designation of wayward Democrats, not to relabel them as Republicans.
The news error was corrected on the later rebroadcast, but I'm sure it subliminally convinced millions of Americans that Foley was a Democrat after having the words "Republican Mark Foley" pumped into their brains seventy times a day by the media for a week.