I don't understand the disdain for Danica Patrick.
She has a couple of things working against her with traditional NASCAR fans:
1. She came from an open-wheel circuit.
Typically, NASCAR fans are slow to warm up to Indy car and Formula 1 drivers that make the switch to stock cars. Most open-wheelers come in with an arrogance, or holier-than-thou attitude (generally NASCAR is considered to be just a bunch of hicks by other circuits), and an over aggressiveness which comes from a false sense of security when they get behind the wheel of a stock car (which leads to them creating problems with their new found ability to rub on the track).
2a. She didn't "earn" her ride.
Warranted, or not, this is the same thing that happened to Jeff Gordon back in the day (and also with Kyle Busch to a certain extent). There's a general disdain for drivers that don't spend at least a couple of years driving trucks, or junior level cars, establishing themselves as an "up-and-comer". Even Dale Jr. drove in the Busch series (now Nationwide) for a while before moving to The Cup full-time.
which leads to...
2b. She's not a "good ol' boy".
She isn't part of a family with NASCAR roots, and she's not from The South. While NASCAR has tried rebranding over the past decade to reach a more diverse demographic, but it's been a rough go changing the mentality that NASCAR is a sport for white red-neck men.
Just my two cents worth.