There's a certain kind of person, usually middle/ upper-middle class, usually white and (in this instance) typically male, who likes to be seen as "one of the good ones" by supporting whatever causes are fashionable in progressive circles at a given time. Maybe they already have some degree of interest in football (the old Stuff White People Like blog went into more detail of this phenomenon in their chapter titled 'The idea of soccer'.) If they're from the southern states they will have an AFL club because you absolutely must support an AFL team to engage socially in Melbourne society, if they're from NSW or Qld they don't really follow Rugby beyond their old private school team because it's no longer fashionable, and a game like League is low-rent, supported by the actual working class and therefore beneath them. Their main motive for following the Matildas (subconsciously, at least) is an exercise in image-crafting. They want to be visible as the kind of person who follows the Matilda's, rather than actually enjoying the game for its' own sake. Having it known they follow women's football/ bashing other men who are indifferent or demeaning towards women's football is another tick on their 'Good, socially conscious male ally' chart and gives them the dopamine hit of believing they stand on the right side of history.
️, srsly
