Most answers here seem to cover the ground entirely ^^. I just wanted to add something specific about my reasons for never writing female protagonists...
Personally, I have long decided I don't enjoy writing female characters (and I am a woman myself). I overthink things and I become paralyzed by futility because I come from some university rhetoric that grilled into me that all female characters follow only 3 archetypes: madonna, whore, "Not lIke tHe OtHeR GiRls" (thus usually a honorary male) and it's impossible to write one outside of this cultural paradigm.
I don't know if I disagree with it or not, really. But I can't unsee it no matter what I do
. It frustrates me so much, and I end up (almost) never writing females because of this. When I do, I don't enjoy it... sucks all joy out of writing for me. Like an OCD.
Thus, I feel much more at home writing males. They're so easy to write, lol, and I can focus with them on some other topic and themes in my stories rather than obsess over the above-mentioned paradigm.
Thus, if you say that somebody doesn't know how to write females and resorts to GB females due to not caring/wanting to learn enough -- that's not necessarily true. They might be just like me. I learned a bit
too much about the perception of female characters in fiction and it has literally horrified me back to writing solely about males
.