Why is it so unbelievable that people would say this? Some celebrities are willing to straight up say to the media that they won't vote for a female nominee:
http://time.com/4071617/ti-woman-president-hillary-clinton/
In a March 2016 CNN poll when asked if the country was ready for a female president, 19% of respondents said no. This question is often a more effective way of getting a sense of the level of opposition to electing a female president than bluntly asking "would you vote for a qualified female presidential candidate?"
http://www.cnn.com/2016/03/04/politics/female-president-poll-results-cnn/index.html
The current numbers of 80% ready/19% not ready are considerably better than in 2008. At that time, only 67% felt the country was ready and 32% thought it was not ready for a female president.
1 in 5 voters thinking the country won't elect a woman is a minority, but it certainly isn't super rare. It's easy to believe Clinton has encountered some of these voters.
I don't see TI at any Clinton rallies, and he didn't say it to her face. Saying stuff to people's face takes an amount of balls that is in most situations beyond human instinct.
Is there a point somewhere you would like to make?