In part this may be a consequence of something known as 'benevolent sexism'. I read a research paper somewhere whereby an experiment was held, women were treated by men, as men had been shown to treat other men. In the end they found that most women believed the men who weren't treating them differently (benevolent sexism) were seen as hostile. Therefore it's possible that some women are so accustomed to benevolent sexism, that when entering a male environment, they struggle to differentiate equality from hostile sexism. Can't find the exact paper, but various results come up around the term benevolent sexism explaining the theories.