Well, the same is true about Trump, so maybe it was partly misogyny. However, she wasn't the top of the ticket, and she had no business or other cred really. I couldn't countenance Palin as a fill-in President if McCain died, and I couldn't give support him after the bad judgement in choosing her. We were not aligned on some issues, but I was confident that he would not have harmed the US.
The earlier point about McCain minus Palin beating Obama, especially had he picked someone like Kasich, is a likely outcome. McCain would have likely had 8 years, and Kasich would be POTUS now.