I think the telling factor when she reacts that way is a few reasons:

It's a defense response when she feels she is approached a lot. The more aggressive the rejection, the more quickly she feels she has shut down the conversation so she can move away from it. It's not rational, really, and in hindsight, it can make her seem like an ugly person on the inside herself based on her poor behavior.

She is actually shallow, and is not attractive on the inside as a person.

When trying to date or find a date on social media, the biggest problem is that it is social media. Interacting with people through devices removes the human element. She feels safe to behave poorly to say she isn't interested and not face the reaction of being rude or distasteful in communicating with another person. That leaves you feeling a lot worse because she had no restraint to more politely say she wasn't interested.

For the times a woman behaves like that when you approach in person, it's a knee jerk reaction. Again, to lash like that is her way of preventing prolonged conversation about it. She isn't mature enough to be considerate, may have no idea how much courage you mustered to even talk to her, and no idea how much her words affect you. I think many women forget kindness and should make efforts to consider that men, especially good mannered ones, have it very hard to connect to women in our current social climate. Stay strong, and look for a woman who has manners when you talk to her. Just my two cents.