Rush Limbaugh calling this lady a **** annoyed a lot of women who were watching the issue and may or may not have cared much about her testimony. His message may have resonated with Conservatives. That's all pretty much irrelevant. I guarantee you there is not a single PR Department in the entire US that went "Hey, we'd like to be associated with that." - that's why they all jumped ship.
No company wants to be included in the hundreds of articles that will be written about this little incident. If the Liberia-FireStone issue taught companies anything was that you have to pick and choose who you'll support and there is no point in supporting a prick. How much money you can make out of him is irrelevant. Unless they're willing to sell to a reduced percentage of the population, companies will almost always distance themselves from inflammatory boils like Limbaugh.