Yes, there is an obligation. If she had gotten smacked in the face with a stray racket and her mouth was all swollen, they would have excused her from speaking to the press. And her job is to play tennis, not to field aggressive questions. It's not the subjective experience of one person either. If you actually paid attention to the story (and other press around this topic) you would have understood that many players have felt similarly about these demands.
“But I think there definitely needs to be more open dialogue on what not only her but everyone on tour goes through. I think we don’t talk about it enough.”
"Martina Navratilova, an 18-times grand slam champion, said the situation had made her “so sad”, but added that the issue was about more than attending post-match media calls.“I truly hope she will be OK,” Navratilova wrote. “As athletes we are taught to take care of our body, and perhaps the mental and emotional aspect gets short shrift. This is about more than doing or not doing a press conference.”