Comments about Fluke were likely just a “fluke”. I am not excusing them, but he talked before he thought. His comments likely reflected his gut feeling about some women, his first impression, his Kardashian moment.
Juan Williams survived (and even thrived) after his gaffe since he is considered a minority and minorities are often given a pass when making poitically incorrect and insensitive remarks.
Limbaugh might not survive though, and he possibly drove the final nail for the Republican in the upcoming election.