Eight of the 10 nominated actresses this year are over 40. And almost none play a character you would want to cross. “With this awards season, we are seeing proof that sexism only sells when it’s the only thing being offered,” wrote Jennifer Siebel Newsom, a filmmaker and founder and chief executive of the Representation Project, a nonprofit that fights gender stereotypes, in an email. She sees the presidency of Donald J. Trump as playing no small part in the nominees’ appeal.