Hello friend! As a fan of Joss Whedon's work I find it very important that I am fully aware of all the bad stuff he has done so that I may be able to appreciate his work but not fall into hero worshiping a dirt bag. Feel free not to go in depth or even answer but if I google searched it I doubt I would find anything negative about him.
GENERAL TRIGGER WARNING
No seriously, he’s really racist.
He supported Patton Oswalt’s rape jokes, anti-semetic jokes, and racist jokes.
He’s just really, really sexist.
He has whitewashed several characters in the Marvel universe. (more here)
Whedon has repeatedly infantized female characters, and when he’s not doing that, he’s punishing them for being sexy, or punishing them for being women. It’s an audacity that he gets so much praise for being a feminist, when he hurts women just as much as the next man.
Whedon is dangerous because he uses hurts women and is worshipped by many as women’s savior in entertainment.
(for more information on whedon’s general shittiness, go here)