This is just another man's opinion, but I was discussing this earlier.
Part of the cultural significance of womens' sport becoming much more prevalant is that it puts female athletes in positions where long held cultural norms are upset. There's centuries of built up cultural standards around women's behaviour that makes people have an aversion to them being openly aggressive and angry. Ask any woman in your life how often they've been called difficult or overemotional in an attempt to undermine their legitimate arguments or grievances. As recently as the 1980's 50% of the population thought women were too emotionally unstable to have political office.
So while to Mary Earps she was just doing what loads of keepers do after a big save, to many of the women looking on, new to women's football, she was doing something they're not supposed to do, and seeing it done and celebrating it feels empowering.
Ironically, the idiot on the previous page giving out about how bad a role model she is and how disgusting it is to see her swearing is the perfect example of this. How many posts has he written about our mens players swearing? Pep swears all the time ("You are tired? Fuck you! Fuck you!!"), no angry comments from him about that.
Another great example of this is Chloe Kelly taking her shirt off in celebration in the Euro's. For a male player to do that is meaningless, we've seen it a million times before, and to Chloe she was just doing what loads of players have done before, but to the watching female public that doesn't usually see womens sport it was a really big statement of equality and empowerment because of the cultural double standards around toplessness and that's why it became iconic and is now on posters and shirts etc.
So yes, small gestures that one person thinks meaningless can have big unintended significance to those watching.
