Many public parks also have beginner sessions or little kid sessions. Do you also get angry at those?
The fact of the matter is that skateparks (and many of the people who frequent them) are intimidating. Some people might show up at a park on a random day and just never skate because they don't feel confident enough or are afraid of doing something that might get them embarrassed--like push mongo, wear the wrong shoes, or grind with both of their trucks.
There is a tremendous amount of hypocrisy in skateboarding, and many of the same people who claim it's for everyone (with their words) will then try to vibe others out (with their actions). I'm a big fan of those that make sure the park locals let the timid ones have a run. Whether they are timid because they are inexperienced, small, young, or a regularly-maligned gender shouldn't matter (and if you don't think female skateboarders are regularly maligned in the skate community, you aren't paying attention).
My 7yo daughter regularly goes to parks with me and she will often refuse to skate, even though I am there. But when we have the park to ourselves, she has a great time. There is a lot that goes on inside each person's head, and their reasons for feeling intimidated are their own.